copy rotation constraint offset

Hi, I’m trying to get a hand bone to copy the rotation of the IK bone I’ve put on the wrist.

When I add the rotation constraint the hand bone is exactly aligned to the ik bone so I use offset to return it to original rotation but it moves to some other seemingly random rotation and now I’m interested to know whats going on, any ideas?

https://dl.dropbox.com/u/1693140/problem.png