If you subscibe to Sprint Navigation, you should be ok, since it does not require an external GPS device. But if you subscribe Telenav, they are yet to update their current version for the mogul to allow you use the internal GPS, you can do what I did, which is to use the one for ATT tilt (
AT&T 8925 (Tilt)). I have been using it for approxiamtely 2 weeks without any issues.
http://splash.telenav.com/sites/att8925-tn52/