The way I understand the X52 setup, in order to use all of the functions on the throttle, you'll need to load the Saitek software (and let it run in the background while playing AH2). The software allows you to map the controller outside of AH2. It also unlocks most of the buttons you've listed.
I have not programed the "mouse wheel" to the left of the 8-way hat switch, or the button to the left of the mini joystick (or the joystick for that matter). The only button I found to be of issue is one of the buttons inside of the y-axis scroll, which acts as the "clutch" button when the option is enabled. It doesn't sound like this is your problem.
Hopefully you'll be able to map all your buttons once you've loaded the software. Good luck. <S>