Think he's after a function that sets mouslook off (so you can use the mousepointer) when he presses (and holds) the button, and turns mouselook on when the button is released.
I've tried tons of combos, and even talked to support, and it seems like it can't be done that way.
Just hope that they'll fix it in a future patch. I've migrated from DAoC (and a few other mmorpgs) that had this feature, and it's addictive. =)
I'm so used to keeping a key pressed down when I want to check a menu, or target a specific mob without having to cycle thru 8-9 of 'em, then just release the key to go back to moving my char around.
But that's me...