If you already have components set up for the angled circle, then the path can be cut with profile toolpath with the "project toolpath onto 3d model" option checked, BUT it probably won't be right if you use a flat-bottomed bit because Aspire calculates the toolpath height from the center of the bit, so the "uphill" side will dig into the part. A ballnose bit won't have that problem, but it will leave a radius on both sides of the bit. That's also true with a fluting toolpath.
This could also be done with a carving toolpath and a small ballnose bit. You'd still get a radius on the inside of the included circle, but it could be small with a small enough bit.
D&S Artistic Woodworking http://www.dsartisticwood.com