Well.. I seldom use IK, (but it certainly has it's value), so maybe I haven't got this quite right, but I believe you will notice that when IK in turned on, hands and feet aquire x,y,z, position dials that aren't ordinarily there. Use these dials to move the hands and feet when IK is activated...if I remember right, the dials essentially move the position of the anchor and the extemity in question will follow as best it can. Be warned: animating with IK on can make things like knees and elbows bend in the most awkward ways unless you've also got limits turned on.