BobCad CAM problem setting origin to center of circle in stock wizard

Hi All,
I have what should be a simple problem. When using the stock wizard I want to set my machine origin to the center of a circle on the part. This is drawn as a circle in AutoCad, not as a solid. When I click on pick origin and then shift-click on the circle it displays 8 points on the circle, but not the center. What am I doing wrong?

Either sketch a point in the center of the circle, so you can use the point as the origin. Or create a new UCS, centered in the circle. With either method, you will want to create them at the z height you want your zero to be set at.