Following this thread, I've been able to get forwarding thru the LMCE working. Basically my network is like this:
IPS -> linksys router --+--> LMCE --> home LAN
+--> wireless router --> guest LAN
So I could confirm the port forwarding from the guest LAN to the home LAN. I still have a problem with either my linksys router port forwarding or my ISP.
BTW, I'm still using 0710beta3 x86.