maybe you could ask this question the the pixlite forum over on ACL
http://auschristmaslighting.com/forums/index.php?board=66.0
I dont know their hardware. I know xlights has been used for E!.31 controllers. E682, E6804, j1sys p12r, p12s, Falcon-16 and others. It is the same interface.
In xLights setup set every universe to 510.
Next go to the TEST tab and verify lights come on in the entire range of your hardware.
If this doesnt work, i can only guess it is something in the setup of the pixlite board itself.
sorry, i cant be of more help
sean