hello / here, at post 28, is a soubroutine for lathe : http://www.cnczone.com/forums/okuma/309768-cnc.html
you may use it as a reference, adapt it for the mill
i am sorry, that is the only thing i have ... besides an updated version inside my pc, but overall it is pretty similar
once you got used with it, it is prety fast editable, but the problem is the duration required to get used with it ... and matrix reloaded is just a movie, so you cant download all the infos into your head
even if you could convert it, you will hit the problem of mill spindle rigidity and keeping the same angle between grooves : spindle does not have a true C axis
somekind of a compromise would be to use a rotary table + a spindle attachement kindly !
ps : try the g-code forum : http://www.cnczone.com/forums/g-code-programing/
maybe you will find someone with a program that requires less time to convert