diff --git a/extensions/superuser-seed/src/main/java/org/eclipse/edc/identityhub/seed/ParticipantContextSeedExtension.java b/extensions/superuser-seed/src/main/java/org/eclipse/edc/identityhub/seed/ParticipantContextSeedExtension.java
index 5a9910ea..df2634a0 100644
--- a/extensions/superuser-seed/src/main/java/org/eclipse/edc/identityhub/seed/ParticipantContextSeedExtension.java
+++ b/extensions/superuser-seed/src/main/java/org/eclipse/edc/identityhub/seed/ParticipantContextSeedExtension.java
@@ -91,7 +91,7 @@ public void start() {
                                         .onFailure(f -> monitor.warning("Error overriding API key for '%s': %s".formatted(superUserParticipantId, f.getFailureDetail())));
                                 return key;
                             })
-                            .orElse(generatedKey.get("apiKey").toString());
+                            .orElse(generatedKey.apiKey());
                     monitor.info("Created user 'super-user'. Please take note of the API Key: %s".formatted(apiKey));
                 })
                 .orElseThrow(f -> new EdcException("Error creating Super-User: " + f.getFailureDetail()));
diff --git a/extensions/superuser-seed/src/test/java/org/eclipse/edc/identityhub/seed/ParticipantContextSeedExtensionTest.java b/extensions/superuser-seed/src/test/java/org/eclipse/edc/identityhub/seed/ParticipantContextSeedExtensionTest.java
index 54e207bc..ed63f155 100644
--- a/extensions/superuser-seed/src/test/java/org/eclipse/edc/identityhub/seed/ParticipantContextSeedExtensionTest.java
+++ b/extensions/superuser-seed/src/test/java/org/eclipse/edc/identityhub/seed/ParticipantContextSeedExtensionTest.java
@@ -15,6 +15,7 @@
 package org.eclipse.edc.identityhub.seed;
 
 import org.eclipse.edc.identityhub.spi.participantcontext.ParticipantContextService;
+import org.eclipse.edc.identityhub.spi.participantcontext.model.CreateParticipantContextResponse;
 import org.eclipse.edc.identityhub.spi.participantcontext.model.ParticipantContext;
 import org.eclipse.edc.junit.extensions.DependencyInjectionExtension;
 import org.eclipse.edc.spi.EdcException;
@@ -27,8 +28,6 @@
 import org.junit.jupiter.api.Test;
 import org.junit.jupiter.api.extension.ExtendWith;
 
-import java.util.Map;
-
 import static org.assertj.core.api.Assertions.assertThatThrownBy;
 import static org.mockito.ArgumentMatchers.any;
 import static org.mockito.ArgumentMatchers.contains;
@@ -60,7 +59,7 @@ void setup(ServiceExtensionContext context) {
     void start_verifySuperUser(ParticipantContextSeedExtension ext,
                                ServiceExtensionContext context) {
 
-        when(participantContextService.createParticipantContext(any())).thenReturn(ServiceResult.success(Map.of(API_KEY, "some-key")));
+        when(participantContextService.createParticipantContext(any())).thenReturn(ServiceResult.success(new CreateParticipantContextResponse("some-key", null, null)));
         ext.initialize(context);
 
         ext.start();
@@ -94,7 +93,7 @@ void start_withApiKeyOverride(ParticipantContextSeedExtension ext,
                 .thenReturn(apiKeyOverride);
 
         when(participantContextService.createParticipantContext(any()))
-                .thenReturn(ServiceResult.success(Map.of(API_KEY, "generated-api-key")));
+                .thenReturn(ServiceResult.success(new CreateParticipantContextResponse("generated-api-key", null, null)));
         when(participantContextService.getParticipantContext(eq(SUPER_USER)))
                 .thenReturn(ServiceResult.notFound("foobar"))
                 .thenReturn(ServiceResult.success(superUserContext().build()));
@@ -117,7 +116,7 @@ void start_withInvalidKeyOverride(ParticipantContextSeedExtension ext,
                 .thenReturn(apiKeyOverride);
 
         when(participantContextService.createParticipantContext(any()))
-                .thenReturn(ServiceResult.success(Map.of(API_KEY, "generated-api-key")));
+                .thenReturn(ServiceResult.success(new CreateParticipantContextResponse("generated-api-key", null, null)));
         when(participantContextService.getParticipantContext(eq(SUPER_USER)))
                 .thenReturn(ServiceResult.notFound("foobar"))
                 .thenReturn(ServiceResult.success(superUserContext().build()));
@@ -141,7 +140,7 @@ void start_whenVaultReturnsFailure(ParticipantContextSeedExtension ext,
                 .thenReturn(apiKeyOverride);
 
         when(participantContextService.createParticipantContext(any()))
-                .thenReturn(ServiceResult.success(Map.of(API_KEY, "generated-api-key")));
+                .thenReturn(ServiceResult.success(new CreateParticipantContextResponse("generated-api-key", null, null)));
         when(participantContextService.getParticipantContext(eq(SUPER_USER)))
                 .thenReturn(ServiceResult.notFound("foobar"))
                 .thenReturn(ServiceResult.success(superUserContext().build()));