C axis with a VFD?

Hello,
I am retrofitting a lathe and replacing the original 30kw Baumuller servo spindle with a 7.5kw three phase motor. The main reason is the controller is dead and repair is not worth it for me money wise. The lathe has a C axis with hydraulic disc brake. I do not need an active C axis, just orienting and locking in place is enough for me. Would this be possible to achieve accurately with the VFD? If so, have anyone perhaps tried it and could give reccomendations for the VFD and motor parameters? How many poles, etc. I need max 6000RPM from the motor, the spindle has a 1:2 belt reduction. 

A VFD is normally not a very good servo system because it has such limited control bandwidth.
It may be workable if orientation is run very slowly, you have a good spindle encoder and do not expect
perfection in the orient angle.