diff --git a/services/acl/Acl.Infrastructure/OpenZaakGateway.cs b/services/acl/Acl.Infrastructure/OpenZaakGateway.cs
index 2dcffd4..5f33ba8 100644
--- a/services/acl/Acl.Infrastructure/OpenZaakGateway.cs
+++ b/services/acl/Acl.Infrastructure/OpenZaakGateway.cs
@@ -8,6 +8,12 @@ namespace Acl.Infrastructure;
 /// <summary>The only code that talks to OpenZaak's Zaken API (ADR-0001).</summary>
 public sealed class OpenZaakGateway(HttpClient http, OpenZaakOptions options) : IZaakGateway
 {
+    // The ACL owns which ZGW statustype/resultaat carries each domain outcome (§8.1). These
+    // omschrijvingen match the seeded BIG catalogus (infra/openzaak/seed_catalogus.py).
+    private const string GeregistreerdResultaat = "Geregistreerd";   // approval outcome
+    private const string GeannuleerdStatus = "Geannuleerd";          // document-timeout cancellation status (S-10c)
+    private const string VervallenResultaat = "Vervallen";           // document-timeout cancellation outcome (S-10c)
+
     public async Task<Uri> OpenZaakAsync(ZaakRequest request, CancellationToken ct = default)
     {
         ArgumentNullException.ThrowIfNull(request);
@@ -48,7 +54,9 @@ public sealed class OpenZaakGateway(HttpClient http, OpenZaakOptions options) :
         ArgumentNullException.ThrowIfNull(zaaktypeUrl);
 
         var eindstatus = await ResolveEindstatusAsync(zaaktypeUrl, ct);
-        var resultaattype = await ResolveResultaattypeAsync(zaaktypeUrl, ct);
+        // Resolve the approval resultaat by name: once S-10c adds the Vervallen resultaattype, taking
+        // the first would be ambiguous (the Zaken API does not guarantee order).
+        var resultaattype = await ResolveResultaattypeByOmschrijvingAsync(zaaktypeUrl, GeregistreerdResultaat, ct);
 
         // OpenZaak refuses to set a zaak's eindstatus unless the zaak has a resultaat
         // ("resultaat-does-not-exist"), so record the resultaat first, then the status.
@@ -62,8 +70,26 @@ public sealed class OpenZaakGateway(HttpClient http, OpenZaakOptions options) :
             "Setting the zaak status", ct);
     }
 
-    public Task SetZaakToCancellationStatusAsync(Uri zaakUrl, Uri zaaktypeUrl, DateOnly datumStatusGezet, CancellationToken ct = default)
-        => throw new NotImplementedException();
+    public async Task SetZaakToCancellationStatusAsync(Uri zaakUrl, Uri zaaktypeUrl, DateOnly datumStatusGezet, CancellationToken ct = default)
+    {
+        ArgumentNullException.ThrowIfNull(zaakUrl);
+        ArgumentNullException.ThrowIfNull(zaaktypeUrl);
+
+        // Distinct from approval: resolve the cancellation statustype + resultaat by name (Geannuleerd
+        // is a non-terminal statustype, so it is never the eindstatus the approval path resolves).
+        var cancellationStatus = await ResolveStatustypeByOmschrijvingAsync(zaaktypeUrl, GeannuleerdStatus, ct);
+        var cancellationResultaat = await ResolveResultaattypeByOmschrijvingAsync(zaaktypeUrl, VervallenResultaat, ct);
+
+        // As with approval, OpenZaak wants the resultaat recorded before the status.
+        await PostAsync("/zaken/api/v1/resultaten",
+            new ResultaatDto(zaakUrl.ToString(), cancellationResultaat.ToString()),
+            "Setting the zaak cancellation resultaat", ct);
+
+        await PostAsync("/zaken/api/v1/statussen",
+            new StatusDto(zaakUrl.ToString(), cancellationStatus.ToString(),
+                datumStatusGezet.ToDateTime(TimeOnly.MinValue, DateTimeKind.Utc).ToString("yyyy-MM-ddTHH:mm:ssZ")),
+            "Setting the zaak cancellation status", ct);
+    }
 
     public async Task<string> GetZaakIdentificatieAsync(Uri zaakUrl, CancellationToken ct = default)
     {
@@ -177,13 +203,23 @@ public sealed class OpenZaakGateway(HttpClient http, OpenZaakOptions options) :
         return new Uri(eindstatus.Url);
     }
 
-    /// <summary>Resolve the zaaktype's resultaattype from the catalogus (the seed defines one).</summary>
-    private async Task<Uri> ResolveResultaattypeAsync(Uri zaaktypeUrl, CancellationToken ct)
+    /// <summary>Resolve a specific statustype from the catalogus by its omschrijving (e.g. "Geannuleerd").</summary>
+    private async Task<Uri> ResolveStatustypeByOmschrijvingAsync(Uri zaaktypeUrl, string omschrijving, CancellationToken ct)
+    {
+        var page = await GetCatalogusAsync<StatustypePage>("statustypen", zaaktypeUrl, "statustypen", ct);
+        var match = (page.Results ?? []).FirstOrDefault(s => s.Omschrijving == omschrijving)
+            ?? throw new InvalidOperationException($"No '{omschrijving}' statustype found for zaaktype {zaaktypeUrl}");
+        return new Uri(match.Url);
+    }
+
+    /// <summary>Resolve a specific resultaattype from the catalogus by its omschrijving (the seed defines
+    /// "Geregistreerd" for approval and "Vervallen" for a document-timeout cancellation).</summary>
+    private async Task<Uri> ResolveResultaattypeByOmschrijvingAsync(Uri zaaktypeUrl, string omschrijving, CancellationToken ct)
     {
         var page = await GetCatalogusAsync<ResultaattypePage>("resultaattypen", zaaktypeUrl, "resultaattypen", ct);
-        var resultaattype = (page.Results ?? []).FirstOrDefault()
-            ?? throw new InvalidOperationException($"No resultaattypen found for zaaktype {zaaktypeUrl}");
-        return new Uri(resultaattype.Url);
+        var match = (page.Results ?? []).FirstOrDefault(r => r.Omschrijving == omschrijving)
+            ?? throw new InvalidOperationException($"No '{omschrijving}' resultaattype found for zaaktype {zaaktypeUrl}");
+        return new Uri(match.Url);
     }
 
     // GETs a catalogus collection filtered by zaaktype (status=alles includes concept + published).
@@ -227,7 +263,8 @@ public sealed class OpenZaakGateway(HttpClient http, OpenZaakOptions options) :
     private sealed record StatustypeDto(
         [property: JsonPropertyName("url")] string Url,
         [property: JsonPropertyName("volgnummer")] int Volgnummer,
-        [property: JsonPropertyName("isEindstatus")] bool IsEindstatus);
+        [property: JsonPropertyName("isEindstatus")] bool IsEindstatus,
+        [property: JsonPropertyName("omschrijving")] string? Omschrijving);
 
     private sealed record ResultaatDto(
         [property: JsonPropertyName("zaak")] string Zaak,
@@ -237,7 +274,8 @@ public sealed class OpenZaakGateway(HttpClient http, OpenZaakOptions options) :
         [property: JsonPropertyName("results")] IReadOnlyList<ResultaattypeDto>? Results);
 
     private sealed record ResultaattypeDto(
-        [property: JsonPropertyName("url")] string Url);
+        [property: JsonPropertyName("url")] string Url,
+        [property: JsonPropertyName("omschrijving")] string? Omschrijving);
 
     private sealed record CreatedDto(
         [property: JsonPropertyName("url")] string Url);
diff --git a/services/acl/Acl.Tests/OpenZaakGatewayTests.cs b/services/acl/Acl.Tests/OpenZaakGatewayTests.cs
index c570fc0..a94f783 100644
--- a/services/acl/Acl.Tests/OpenZaakGatewayTests.cs
+++ b/services/acl/Acl.Tests/OpenZaakGatewayTests.cs
@@ -410,7 +410,7 @@ public class OpenZaakGatewayTests
             Gateway(ApprovalStub(rec, new OzRoutes { ResultaattypenJson = "{}" }))
                 .SetZaakToEindstatusAsync(new Uri(ZaakUrl), Zaaktype, new DateOnly(2026, 6, 4)));
 
-        Assert.Contains("No resultaattypen found", ex.Message);
+        Assert.Contains("'Geregistreerd' resultaattype", ex.Message);
         // Resolved the eindstatus + queried resultaattypen, but posted nothing.
         Assert.Equal(-1, rec.IndexOf("/resultaten"));
         Assert.Equal(-1, rec.IndexOf("/statussen"));