I haven't got any monitor plugged into my fit-pc2 too.
My fit-pc2 is running Ubuntu Linux 9.04 Jaunty - kernel 2.6.28-14.
When I want to remote access my fit-pc2, I use open source protocoles : VNC, XDMCP, SSH -X, etc. ...
The screen resolution is always perfect (higher than 800x600).
But I haven't tested "LogMeIn" ...
If your fit-pc2 is runnning GNU/Linux, maybe could you try this to force resolution

:
http://ubuntuforums.org/showthread.php?p=454217