Here is a zip with some files I used to quickly test Lightmaxx fixtures with dmxusbpro (as I finally didn't use the lights, all those patches are quite ugly). There are different PAR models, maybe one of those included will work for you ; the parameter is the dmx channel.
I think there are DIP switches on the PAR you need to set correcly to be in DMX mode and to set the channel (sorry, I don't have the manuals anymore).
Too bad I did't keep a copy of the manuals (but I didn't keep the PAR neither). You could try to contact MusicStore...
On a french speaking forum, I see that DIP switch 10 should be set to on to set the PAR into DMX mode. Then the switches starting from 1 are used to set the DMX channel. So 1 & 10 on should allow you to control the PAR on channel 1.