Need Help! Milling a convex radius with solid model

I have V25 and want to make scope base for a round receiver. I modled the radius by subtracting the radius from a rectangleular solid and setup my milling stock, but can't find the proper feature to mill with a ball mill.

Just talked with BobCad support and got the answer. I had been only selecting the radius in "Slice Planer" feature when it should have been the whole model. And using the tool center rather than tool tip. Those changes made the whole thing work.