ipfw pipes

[synrat]

I'm trying to figure out ipfw/pipes setup.
The requirement is to provide more or less exclusive pipe
for voip service ( vonage ) that goes through ipfw nat.
I know this isn't QOS and I would appreciate advise on QOS as well,
but for now I just want to get this working and tested.

I want to specify a 64kbs pipe for voip with the most weight and
then give the rest of the bandwidht to all hosts behind the NAT,
no other pipes. Is this sufficient or do I need to setup rules for ext 
and int interfaces ?
Do I also need to specify the entire bandwidth available  via Internet 
connection and other pipes for the remaining hosts or does leaving 
everything else out give the remanining bandwidht to other hosts ?

thank you all

        ${fwcmd} add pipe 1 ip from 192.168.1.2 to any out
         ${fwcmd} add pipe 2 ip from 192.168.1.2 to any in
         ${fwcmd} pipe 1 config bw 64Kbit/s queue
         ${fwcmd} pipe 2 config bw 64Kbit/s queue