I am sure a version of UASD is coming soon that will support the BC396XT.
One thing you could do temporarily is to use FreeScan to load your existing BC396T UASD file and then upload it to the BC396XT. FreeScan can read (import) UASD files and can upload to the BC396XT.
See: ScanNow.org - The Home of FreeSCAN!
Sites will have to be added to each trunk system in the 396T files before loading them into the XT.