Snow Leopard comes with a great little new command in mcxrefresh, which as you might have guessed refreshes policy information. This allows you to request a new set of policies and provided the command returns with no errors the process has completed successfully (exit's 0). Use a UID using the -u option and use a short name using the -n option:
mcxrefresh -n cedge
You can also use the -a option, which prompts for authentication when dealing with Active Directory. There's not really a lot to mcxrefresh, but what there is turns out to be really useful.