Used X360CE (http://code.google.com/p/x360ce/downloads/list) to enable “pass through” (ignore device) functionality. Also means that if I ever want to use my game-pad, I don’t have to worry about it conflicting with the joystick.
For those who’ve not used X360ce, it’s pretty simple.
Unpack the archive to the Tribes\Binaries\Win32 folder (so it is in the same location as the TribesAscend.exe);
Run X360ce.exe to launch the configuration program;
Go to the appropriate device tab - typically Controller 1; but could be any of them if you have more than one input device - the sub-tabs for each device should help you identify which is which.
Go to the Advanced sub-tab
Check the Pass Through check-box on the device(s) you want the game to ignore.
You should see the coloured square in the Device Tab go from green to red to indicate it is now disabled. Save up, and exit the program. You should notice it has created the file “xinput1_3.dll” (or similar) in the same folder.