Mark,
I thought you had to put it into the masq file fragment, expand it and then reboot, but theroretically it should just work if you entered them in the shell as it adds them directly to the masq file and applies it right?
I am not too sure on where they go actually, but I am sure they are the right rules.
Sorry I cannt be of more assistance, once I am able to get a test box up I can fiddle a bit more with it.
Cyrus Bharda