ive finished experimenting on my vista to enable to dual log in RF..
these are the steps
1.download ShellRunas
2.extract to a folder
3. after extracting create a shortcut
4. right click on the newly created shortcut shellrunas
5. on the target delete everything and then input /reg then press ok
6. run rf online
7. after you run rf online right click again on the rf shortcut and click sign as different user..
Note: please make sure to have another usser account to enable this...