There was another thread on a similar topic but it got all confusing...
Anyways, here is the DTD string I used to get 800X480 on the Lilliput 619:
4C 1D 20 FC 30 E0 14 10 20 38 37 00 00 00 00 00 00 1E
The first numbers are the refresh rate and I fiddled with that.
I also have posted a driver for 800X480 for Intel G965 series onboard graphics w/ this Lilli in the other thread.