I've only got one functional hand so I reconfigure movement keys to the up and down buttons on my microsoft gaming mouse. This wasn't a problem in prior Fallout versions, but now it tells me those keys are "reserved" I remapped them to the up and down keyboard keys and attempted to configure my mouse to recognize those, but that doesn't seem to work on the steam platform/ Any advice?

Autohotkey?

I don't see how that would remap a key to my mouse. Am I wrong?

There is a lot of reported remapping problems, please report your here to make it get logged:

http://www.gamesas.com/topic/1544248-bug-report-index-pc/

It might actually be possible, at least to a degree. AutoHotKey does include mouse functions:

https://www.autohotkey.com/docs/KeyList.htm#Mouse

This thread will be a good place to ask to find out for sure:

http://www.gamesas.com/topic/1546356-workaround-for-hard-bound-keys-autohotkey-tutorial/

z