Below are the RS joystick button defaults, what functions are you trying to map to buttons 7 and 8?
The following text was extracted from LucasArts Technical Support for RS:
Joysticks are fun.
We highly recommend using a joystick. Joystick buttons can be reassigned, but all joysticks (and gamepads) default to the following button assignments:
Button1: Fire Primary Weapon
Button2: Fire Secondary Weapon
Button5: Special Action (S-foils, etc)
Button6: Link Weapons
Button8: Cycle Camera Views
Button9: Right Brake
Button10: Left Brake
To disable joystick control of your craft while flying, press Ctrl-J. To re-enable joystick control, press Ctrl-J again. Joystick control will automatically be restored when the level ends, in any manner.
If you are having problems controlling your craft while flying with a Joystick. Check the fine-tune control knobs on your joystick. Make sure they are centered. If the problem persists, re-calibrate your joystick, either through the Launcher (Hardware Configuration button) or through the Windows Control Panel.
Also, when using a joystick, make sure you're not accidentally bumping or moving the mouse while playing Although the craft will auto-center itself if this is done, it can be very disorienting, and make the craft difficult to fly. One solution is to disable mouse support by pressing Ctrl-M while in-flight.
Ties are flies, swat'em!