VPN behind a router

[Helio Santana <heliosantanaperez_(_at_)_gmail_(_dot_)_com>]

Hi,
first excuse my english, please.

I'm trying to make a VPN between 2 computers with OpenBSD behind a
router that connected to internet (See schema)

Private LAN4 ------ OBSD_4 ---- Router_4 ---- Internet ---- Router_5
----- OBSD_5 ---- Private LAN5

Every OBSD has 2 net cards 1 connected to router, and the other to the
hub in private lan.

I have made all steps explained in "man vpn".
My private Lan's are 192.168.4.0/24 and 192.168.5.0/24. The Lan
between OBSD and router's are 192.168.41.0/24 and 192.168.51.0/24.

Routers redirect all incoming trafic to his respective OBSD and have
his Firewalls disabled.

External IP Router_4 is A.B.C.D, External IP Router_5 is W.X.Y.Z

All computers in LAN4 has access to internet and can make a ping to W.X.Y.Z...

I can make an ssh connection from OBSD_4 to OBSD_5... even from an
conection from Internet.... I can make a ping, etc.

The only way I have make possible to connect the VPN is configuring
routers as modems (I don't know whats the name of this in english, in
spanish 'monopuesto').

But I need to do configuring both routers as routers (in spanish 'multipuesto').

Thanks in advance,
Helio.