For now, I'd recommend:
-follow the instructions on the "building for dream" page on how to
get the proper source code, passing a "-b android-1.5" parameter to
repo init, and starting from and ADP1 running 1.5.
-once you have the entire source tree, "source build/envsetup.sh",
then "choosecombo device release generic userdebug". Run "make", and
then flash with "fastboot flashall".
I'm working on streamlining some of this process. No ETA.
JBQ