Maybe this thread will help.

http://forums.teamestrogen.com/showthread.php?t=52906

Also I am totally guessing here, but I'm wondering if you might need to change your riding position a bit. You might be leaning forward by bending mid-back, rather than bending from the hips. When you hinge at the hips, it shifts the weight forward and lifts the back of your butt. Of course that can sometimes lead to different saddle issues, but it's worth considering.

Good luck.