Soetingr,  I see that this has gone unanswered for sometime. However, I would like to take the opportunity to answer the question in the event others stumble upon this.   This is expected behavior. RBAC only works with the System access zone by design.
Hi,  We have mutliple accesszones for different customers. To be able to add shares we create a script that works with the REST Api. This script works fine with the System zone, but we are not able to get it working with any other accesszone. We found that adding the ISI_PRIV_PAPI privilege to a user inside a access zone is impossible. It is completely not possible to add privileges to any user that is not in the Systemzone. Can anybody think of a solution?  Thanks,  Robert
RBAC & Accesszones - Privileges