Can someone help me get my universal remote working?

I have linux installed on an apple tv and can not get my universal remote working for the life of me.

I have a URC MX-900... I can use the pronto hex codes with it... I also have a logitech harmony remote so I can get IR codes from there to program my MX-900 if I have to.

Anyways I can not get anything other than the standard apple remote ir codes to work. Do I need to get or make a custom keymap.xml? where should it be placed and what should it look like? I guess it would be awesome if someone could give me or direct me to a place that has step by step instructions. I am just not getting it.