diff --git a/tests/acceptance/Steps/EenZaakOpenenSteps.cs b/tests/acceptance/Steps/EenZaakOpenenSteps.cs
index 6dd2fc4..493fb55 100644
--- a/tests/acceptance/Steps/EenZaakOpenenSteps.cs
+++ b/tests/acceptance/Steps/EenZaakOpenenSteps.cs
@@ -29,9 +29,12 @@ public sealed class EenZaakOpenenSteps
             Bronorganisatie = values["bronorganisatie"],
             VerantwoordelijkeOrganisatie = values["verantwoordelijkeOrganisatie"],
             Vertrouwelijkheidaanduiding = values["vertrouwelijkheidaanduiding"],
-            ZaaktypeUrl = new Uri(values["zaaktype"]),
-            InformatieobjecttypeUrl = new Uri("http://openzaak/catalogi/api/v1/informatieobjecttypen/dip"),
+            ZaaktypeIdentificatie = "BIG-REGISTRATIE",
+            InformatieobjecttypeOmschrijving = "Diploma",
         };
+        // The ACL resolves the zaaktype by identificatie (S-27); the scenario's zaaktype URL is what
+        // the catalogus resolves it to, so the created zaak still carries that URL.
+        _gateway.ResolvedZaaktypeUrl = new Uri(values["zaaktype"]);
     }
 
     [Given("today is \"(.*)\"")]
@@ -41,7 +44,7 @@ public sealed class EenZaakOpenenSteps
     [When("the domain asks the ACL to open a zaak")]
     public async Task WhenTheDomainAsksTheAclToOpenAZaak()
     {
-        var service = new AclService(_gateway, _defaults!, new FixedClock(_today));
+        var service = new AclService(_gateway, _defaults!, new CachedZaaktypeCatalog(_gateway, _defaults!), new FixedClock(_today));
         _returnedUrl = await service.OpenZaakAsync(_registration!);
     }
 
diff --git a/tests/acceptance/Support/InMemoryZaakGateway.cs b/tests/acceptance/Support/InMemoryZaakGateway.cs
index d16d353..f8fc104 100644
--- a/tests/acceptance/Support/InMemoryZaakGateway.cs
+++ b/tests/acceptance/Support/InMemoryZaakGateway.cs
@@ -14,6 +14,11 @@ public sealed class InMemoryZaakGateway : IZaakGateway
     public (Uri Zaak, Uri Zaaktype, DateOnly Datum)? Approved { get; private set; }
     public (Uri Zaak, Uri Zaaktype, DateOnly Datum)? Cancelled { get; private set; }
 
+    // The URLs the catalogus resolves the configured identificatie/omschrijving to (S-27); settable so
+    // a scenario can pin the zaaktype the ACL should default-fill.
+    public Uri ResolvedZaaktypeUrl { get; set; } = new("http://openzaak/catalogi/api/v1/zaaktypen/big");
+    public Uri ResolvedInformatieobjecttypeUrl { get; set; } = new("http://openzaak/catalogi/api/v1/informatieobjecttypen/dip");
+
     public Task<Uri> OpenZaakAsync(ZaakRequest request, CancellationToken ct = default)
     {
         Captured = request;
@@ -37,4 +42,10 @@ public sealed class InMemoryZaakGateway : IZaakGateway
 
     public Task<Uri> StoreDocumentAsync(DocumentRequest request, CancellationToken ct = default)
         => Task.FromResult(new Uri("http://openzaak/documenten/api/v1/enkelvoudiginformatieobjecten/acc-doc"));
+
+    public Task<Uri> ResolveZaaktypeUrlAsync(string identificatie, CancellationToken ct = default)
+        => Task.FromResult(ResolvedZaaktypeUrl);
+
+    public Task<Uri> ResolveInformatieobjecttypeUrlAsync(string omschrijving, CancellationToken ct = default)
+        => Task.FromResult(ResolvedInformatieobjecttypeUrl);
 }