Hi, Jonesy, you seem to be looking for the same thing I'm looking for: I think I found the commands in FSUIPC, but you might be into FSX, whereas I'm into FS2004, and our FSUIPCs may be different. Also, you seem to want to use your throttle quads (Saitek?), whereas I'm using keyboard inputs (I modified a keyboard's PC board to use as a 'switchboard' of sorts for switch inputs), so it looks like we seek similar information for different input methods, so here goes...
In the FS2004 version of FSUIPC, in the drop-down menu, I found the starter commands to be "Toggle Starter 1", "Toggle Starter 2", "Toggle Starter 3" and "Toggle Starter 4"; for fuel valves, I found them to be "Toggle Fuel Valve Eng 1", "Toggle Fuel Valve Eng 2", "Toggle Fuel Valve Eng 3" and "Toggle Fuel Valve Eng 4". You'll want to find your commands under the "Buttons + Switches" tab of your FSUIPC for your quadrants, whereas I found mine under the "Keypresses" tab for my custom "gizmo". See what happens...good luck.