There are sevral ways.How does Mastercam handle a 4th axis?
It really matters what you want to do or make.
Do you want to use Axis substution or true 4axis ?
Do you want to use exsiting 3d model or Surfaces or solids?
I do this all the time.Can I wrap a 2D drawing around a cylinder for engraving with a 4th axis?
Draw it in 2d program it on the first Parameter page, use Rotary Axis tell it the axis to Sub and if it is 2d to Roll it and the and the major Dia.
Just a few thoughts.