route on PIX

[Xaos <xaos () compulink gr>]

Hi...
I'm not sure if it's the right list to send the question but it's the 
only one i've got so here goes nothing... :-)
The situation is like this... Somebody at my work decided that it's my 
job to make some changes to one of our clients' systems but the problem 
is that i'm supposed to make the change to a PIX firewall and i've never 
even seen one before today let alone configure one...

This is how the network is set up now (IPs are changed to protect the 
innocent :-)... Every device has subnet mask 255.255.255.0 so i'll leave 
that out...
The PIX is set as default gateway on the DC
There are two routes configured in the PIX
route outside 0.0.0.0 0.0.0.0 192.168.0.2 1 and route inside 10.0.1.0 
255.255.255.0 10.0.0.199 1

[Zyxel 10.0.1.1]---ISDN Line---[Zyxel 10.0.0.199]---Ethernet---[PIX 
10.0.0.15]---Ethernet---[Domain Controller 10.0.0.20]
                                                              |
     [Internet]---ISDN Line---[3COM 192.168.0.2]---Ethernet---|

I have to add another ISDN router (Cisco 803) that will communicate with 
the lan in the same way the two zyxels do...
I've already created another route inside 10.0.2.0 255.255.255.0 
10.0.0.200 1 for the new network and i've managed to ping the remote 
server from within the pix but i just can't get the domain controller to 
ping the remote server (say 10.0.2.2) unless i set up a static route on 
the DC itself...
But i don't think that's right cause that worked even wihout making any 
changes on the pix which means that the connection was bypassing the 
firewall...
Any ideas?

Thanx for your time.... :-)