This is quoted from the Energy ROM FAQ:
ActiveSync Issues (23081 Version)- Go to Start -> Settings -> Connections -> USB to PC
- Uncheck the last, "Ask me first about USB...." box
- Make sure the "ActiveSync (Sync with Outlook)" bubble is filled in.
- You may need to restart the phone for ActiveSync to start working)
Dunno if it will help, but I came across it right after reading this thread so I thought i'd chime in, I flashed the Leo ROM today and love it so I understand you wanting to use it for sure. Good luck!