Should be stickied here somewhere, but I'll help you since you already done most of the work. If you edit your shortcut to the client to include -smp, when it finished this wu it will start on a smp one. So the target should be
Code:
".....\Fah-something.exe" -verbosity 9 -forceasm -smp
Edit: it will finish the current wu first, which could take awhile ( those ambers don't use SSE2/3 afaik, their really slow ).