HAAS OM-2 4th axis servo motor

Hi All, newbie here :-) I have recently acquired a used HAAS OM-2 (2006) that came with a 4th axis drive but not with a rotary. I am trying to prevent spending $13000 on a new Rotary from HAAS so i am hoping i can build my own and drive it with the HAAS 4th axis drive. The idea is this - buy the correct HAAS (Yaskawa) servo motor for the 4th and wire it up then build a rotary around that. The problem is i cannot work out what the correct Yaskawa servo is for this. I read several Yaskawa manuals and tried to work out through google what motors would works but so far came up wanting. I understand this would be a brushless, Sigma-1 motor, with brake, but i can't work out the exact model. The HAAS site lists one such motor but other than the HAAS internal part number there is no information. Does anyone know what servo i need for the OM-2 4th axis? The servo amp in the machine is a 32-5550J 30A smart amp assy. The other servos in the OM-2 are Yaskawa SGMP-04A2HA11 or similar, so 400W, 200V. thanks for looking :-)

You can choose a motor with bigger torque, there is no harm using a bigger one, only you need to make sure the motor flange can be fitted on the rotary table.

Thanks for the response! I am looking at a brushless motor for a HA5C that someone is selling, i think this will work for me.