How to change the background of a rio

t99

yesterday I installed freebsd 6.2 with a rio WM.
the problem is I just copy the exce file from the dir where I install plan9port.
Now, where should I create my conf  file  for  it  and  what  should  I  put  in
the file in order to change the background.

PS:  I 've tried wmii+ixp-20070508 but it just not work with my keyboard.
I've read some stuff from this site but when I press alt+enter on thing happen is happen.
Also is  that  possible that I did not set the modkey  properly. If yes how should I conf it.