networking in xen

Hi all,

I have a question about networking inside Xen.

My ISP provides me with 2 ipnumbers that can be obtained via my cable modem. So two computers can connect to the cablemodem and each get their own public ip number. This is great.

My opensuse 11.1 server has two nics, one connected to my internal lan, one connected to the cable modem. ( two switches )
eth0/br0 is my local network, eth1/br1 is my external interface.

I have setup ( for now ) my xen server so that the br1 of Dom0 does a dhcp request, and gets a public ipnumber. This interface works good and I can forward traffic thru this interface.
Now I have setup a virtual machine with 2 interfaces, one in my internal lan, and one to obtain a public ip number.
The virtual machine does dhcp and gets a public ipnumber from my isp. This ip is in another subnet that the ip number from the br1 in my Dom0.

The gateway etc is all set in the virtual machine and everything seems just fine. I can ping the default gateway in the virtual host. Whenever I do a traceroute to a public host, the first step is the gateway of the Dom0. This implies that the virtual machine cannot be contacted to/from the outside.

Did I explain the situation enough ?
Anyone seen this before, or is it default behaviour ?
And ofcourse, how can I fix this.