With Google Voice on SP1 and SP2, both can use ITSP Profile A where the only necessary setting is:
Service Providers -> ITSP Profile A -> General -> SignalingProtocol : Google Voice
Both SP1 and SP2 Voice Services should be set to:
Voice Services -> SPx Service -> X_ServProvProfile : A
Voice Services -> SPx Service -> X_SkipCallScreening : (checked)
The one that's not successfully connecting almost certainly has the wrong credentials:
Voice Services -> SPx Service -> AuthUserName
Voice Services -> SPx Service -> AuthPassword