How to get COM-port to work trough docking-station from Dell?

Hi!
I have a Dell Latitude D830 that is connected to an Dell D-dock docking-station.
The Ethernet-port is working and all USB-port and VGA are all working, but i can’t get the COM-port to work.

I only find one COM that is the one internal on the laptop. The other is not detected in normal way.

Some info:
~> cat /var/log/boot.msg | grep serial
~> <6> 0.848338] serial8250: ttyS0 at I/O 0x3f8 (irq = 4) is a 16550A
(This is the internal COM-port)

Is there a way to detect/add another serial com-port?