Unless the MXOP software has a way to add IR codes via direct entry of HEX codes (copied from the Pronto files, using the freeware ProntoEdit from this site), you will need a remote that has the X-10 IR commands built-in, to teach the MX-1000. Smarthome has a remote that will send X-10 both in IR and RF, but I am not sure it can send unit codes 11-16. [Link: smarthome.com]

You can also try the more expensive OFA remotes.