Shilo,
Bring up clipboard, and then use "H" key to toggle mouse on or off. Really not necessary to have clipboard up, but this helps to see the cursor.
Also, there are a couple of ways to set mouse toggle to a joystick or even mouse button. That is what I have done to enable my "mouse look". This feature will point my view in any direction that I move my mouse.
Tracerfi,
Are you using mouse or joystick to fly? As far as I knew, if a joystick was plugged in the new "mouse fly", was disabled. If you are using mouse to fly, there is a command to toggle back to AH2 mouse control IIRC. The response to the control was a bit different still though. It took most of the alpha testers, including myself to get used to the new mouse control system, but with some adjustments it grew on some of us.