Well, you can just start the Service via ssh with:
$ sudo touch /private/etc/ScreenSharing.launchdAnother way I which I did not check is to execute this statement:
$ echo -n enabled > /Library/Preferences/com.apple.ScreenSharing.launchdWow, that sime! Now you can connect to your machine via VNC and work with the mouse. ;-)
I hope this helps you like it helped me a lot.