allowing gre through 3.0 firewall

["meeps" <meeps@charter.net>]

hello, have seen this issue touched on elsewhere but never resolved.  am
trying to connecto to our corporate pptp server on the internet using my xp
client behind my 3.0 firewall.

192.168.168.2 --> openBSD firewall (pf and nat running) --> corporate pptp
server

would appear that i need to pass gre packets into the 192 client, is this
correct?  if so, can someone tell me how to set this up in pf.conf and or
nat.conf?  thanks...