i am still on Leopard, so it may be possible that i fail to understand your problem properly. I suggest this: copy this line:
do shell script "qs" and save it using Script Editor.app Assign it the hotkey shortcut you want to launch Quickislver with, by going to Quicksilver>>Preferences>>Triggers and setting up a trigger like <name of script you saved above.scpt> <run> (Note: you need the "Command line plugin" installed for this to work)
