bassmannate wrote:I've tried changing the xml files directly
WHICH xml files?
As has been stated many times elsewhere on the forum, there are two files you need to be aware of when manually adjusting joystick bindings:
(1) data/input/joysticks.xml: which directs FG to which bindings file you wish to use;
(2) data/input/joysticks/{brand name}/{blah}.xml: the bindings themselves.
You didn't specify which OS you are on; but particularly if you are on Windows, chances are that the current configuration is kicking you into a generic "default" bindings file (again, search this forum if you want the full explanation). Edit the first of two above (and make sure to remove the <!-- --> tags around the statement you wish to have an actual effect) to direct FG to load the bindings file you want to use; otherwise, no amount of editing on that second file will have any effect.
Sorry for my terse tone -- I really do wish to welcome you to our community. However, please be mindful that many of these problems have been addressed many, many times, and the answers you seek might already be here without someone having to type them all over again!