IK handle controlling hand rotation

[-undertow-]

I dunno if this is a newbie or even stupid question, but, say for an arm and hand, you have an IK handle controlling the arm, and the hand keep's it's orentation to the next bone up (so the hand is alligned with the forearm no matter where you move the IK handle).
Can you get the IK handle to control the hand's rotation without having to use an orient constraint (how i do it now), and be able to blend it on and off?
If you use an orient contraint with the IK handle, you don't really get the ability for FK, as the hand will always keep the rotation of the IK handle. And you can't blend the weight of the constraint to off for smooth changes.

[perseus2]

put an extra joint in the forearm, which would control the hand rotation.

Create your arm IK handle from the shoulder to the forearm joint; this way the joint is free to rotate using FK.

Move the IK end-effector to the wrist so that its placement is more intuitive. Select the end effector in the outliner, then move it to the wrist using the point-snap.