altering hip contact angle of a belt

[paratracker]

I have a belt that is essentially an ellipsoid (or oval) where the designer flared the oval out to fit hips, but there's too much of a difference between size at the top of the belt versus size at the bottom, so once you stop it from penetrating the avi's body, you end up with the lower ellipsoid dimensions flaring out away from the hips.  Can anyone tell me how to change the angle of that 'flare' or difference between size of top of belt ellipsoid and bottom of belt ellipsoid?