Xenserver with Pfsense - Ping Timeout 2 of 3

[VooDooswe]

Hi!
I've installed pfsense in a vm on my xenserver.
Its config is:
Cpu: amd athlon II x3
Ram: 4gb
Nic: 1x Realtek (internal motherboard) 1x D-link quad port (its in the supported hardware list)

The problem that i am having is that right now i've only one cable connected to the d-link card which is used to get the internet (incoming and outgoing traffic) the internal realtek lan card is acting as a LAN-port to the internal network.
The internal traffic is working as it should with no ping timeouts etc. put when i try to ping google.com from one of the computers on the lan it will timeout 2 of 3 packets.

Does anybody have any suggestion or tips?

//BR
Patrik