Maybe I didn't read your post right but all you have to do to run it is go to \Storage Card\SASHIMI\Program\2577 and run the autorun.exe just like the instructions say. You do it right after a flash.
The only thing UC will do (I think) is start SASHIMI automatically after a flash which I would prefer to not happen so you can change anything around that you might need like the screen from turning off when SASHIMI is running since it takes a while for all the CAB's. (yeah yeah I know thats a long run on...)