Lathe with C axis

I decided to make a separate post for this. I have a Mazak Qt20 that is retrofitted with Linuxcnc. Currently I have a x and z axis.I want to mount a live spindle to the turret and use the spindle as the C axis. This spindle drive is a A06b-6044-h011 AC servo drive, I'm not sure what motor it uses, there is no tag on it. The motor drives a gearbox that drives the spindle and the spindle is connected to an encoder that is driven with a toothed belt. The encoder is a Tamagawa RFH1024-22-1m.
How should I connect the components ? Do I need to connect the encoder to the drive, as it currently is, or should I connect it directly to the Mesa card? Is there any other I/O pins that I should connect to or from the drive, other than enable, gnd, -V, 0V? How do I set this up in my INI and Hal configurations? 

I will attach a wiring diagram of the drive. 

I had a look at it today again and realized I won't be able to make it work. The backlash in the gearbox will not allow me to machine the part accurately. I'm won't be attempting this any further. Unfortunately this machine was not designed to have a c-axis.

You can add a second servo motor with a gear like HAAS does
I think it's better if the second encoder goes to the mesa card.