Sip Trunk

Hi

I already have my PBX system working in my LAN network, so I can make calls between extensions.

Now I want to make an outside call.

First of all I buy an SIP trunk from my ISP provider and they tested and work properly.

Now I want to use the PBX system to make an outside call.

I create a SIP trunk with this parameters

General Settings

Trunk Name: Basic
Outbound CallerID: 4 + number given by the ISP

Trunk Name: Dinamik
PEER Details:
disallow=all
allow=alaw
host=xxx.xxx.xxx.xxx
insecure=port,invite
type=friend
nat=no
qualify=yes
context=from-trunk

User Context: Inside
host=xxx.xxx.xxx.xxx
insecure=port,invite
type=friend
nat=no
qualify=yes
context=from-pstn

Both host are the same, (atually I do not not why :S)

And a outbound route using that Trunk.

Here comes my questions, The ISP gave me this information

IP-Server (RasPBX) xxx.xxx.xxx.10
IP- Gateway (The modem they left me) xxx.xxx.xxx.9
Number- xxxxxxx
SIP server - (it is the one I am using as host) xxx.xxx.xxx.xxx

So in the network interfaces the gateway should be my router because if I set the gateway they left me, the RasPBX lose the connection with the LAN.

With this configuration the Trunk Does not work.

Any ideas?

Thanks in advance

any help would be much aprecciated