I have tested this in a SL-C1000 running pdaXii13, but it should work equally well in pdaXrom Beta1 or Beta3. Not sure about other versions, please let me know if you encounter any problems.
To enable autorotate when the screen is twisted, just add this line to ~/.fluxbox/keys:
None XF86RotateWindows :ExecCommand rotate.sh
This works with the rotate.sh script in pdaXii13, I don't know if pdaXrom has that same script. If you have problems, again let me know. I can post the contents of the rotate.sh script if necessary (it's just about 10 lines of code.)