com security s vista beta 5308 release

Hello. I developed a COM object in Windows Vista Beta 5270 release which registered with Sync Center. I used as a model the sample code from Windows Vista SDK. It all worked fine until I installed the new 5308 release of Windows Vista. Now, the code fails when trying to register the dll.
This is the sample code that fails:
hr = CoCreateInstance (CLSID_SyncMgr,NULL,CLSCTX_SERVER,IID_ISyncMgrRegister,(LPVOID *) &lpSyncMgrRegister); if (SUCCEEDED(hr)) { hr = lpSyncMgrRegister->RegisterSyncMgrHandler(CLSID_SyncMgrHandler, wszCLSIDDescription,0 /* dwSyncMgrRegisterFlags */);
AssertSz(SUCCEEDED(hr),"Registration Failed"); hr = lpSyncMgrRegister->Release();
}
The call on lpSyncMgrRegister->RegisterSyncMgrHandler returns E_ACCESSDENIED. Can anyone give me a clue about what's happening here. I tried the sample code provided with the Windows Platform SDK and it works just the same.
I even tried to use hr = CoInitializeSecurity(NULL, -1, NULL, NULL,RPC_C_AUTHN_LEVEL_NONE, RPC_C_IMP_LEVEL_IMPERSONATE, NULL,EOAC_NONE, NULL); before the code section specified above, but has no effect.
Thanks and the best regards,
Paul Chis.