I wanted to do the same as Neil did and even after trying both
solutions
I could not have the script end until Safari quit... It basically
waits
until the process which it started would end.
This is what I'm using now that works just fine:
on run
set cmd to "(INSERT FULL PATH TO)/Webkit/WebKitTools/Scripts/run-
safari > /dev/null 2>&1&"
do shell script cmd
quit
end run