Trying to turn on polar interpolation. Need a little help plox.

Hi guys.
Ok so I'm doing some face contouring with X & C axis (no Y).
My program is about 215 lines long. But I was told to use polar interpolation.
Our machine has it. G112 & G113.

But in mastercam x5 educational version it does not use it.
I read through the post file and it says. To use Polar Interpolation I must activate
MI 5 , or MI 4. Can't remember which. I read that MI mean miscellaneous integer.

Does anyone know where or how you turn on miscellaneous integer 4 or 5?
Is it within MC or is it inside the post?

Thanks in advance.