Sounds like the LAN to LAN might be L2TP? I dont believe pfSense supports this yet, perhaps in a few versions. Or you could try posting a bounty to help epedite the addition and support the project. Otherwise you could try IPSec between the two with DES/MD5 and small bit keys, maybe it supports those? I'd say try to figure out exactly how the Vigor 2800 does IPSec then have pfSense mimic those configurations.