One option ... you can use an offline conversational system like our KipwareT conversational.
KipwareT will output Okuma ( and also Fanuc ) code out-of-the-box ... no post or anything else required.
One big advantage ... if you put KipwareT on a laptop it is not tied to the machine. You can move it around to program different machines ... and you don't have to program at the machine in the shop but rather you can program anywhere ... in the shop, in the office, from home.
If you have interest you can additional info at the KentechInc.com website here : KipwareT - Conversational Cam and Conversational CNC Programming Software for creating G code programs for CNC lathes and turning center machines.