Help setting DISPLAY to an ipmasq'd machine.

[maillst]

I need some help figuring out how to set the display variable to a machine that 
is being ipmasq'd on my network.

Here is what I have:

Xserver_machine (192.168.1.3)
        |
        |
IPMasq_Machine (192.168.1.1 on internal network)
        |      (x.x.x.x on internet)
  ------------
  | Internet |
  ------------
        |
Company_Firewall (y.y.y.y on internet)
        |        (10.a.b.c on company lan)
Work_linux_box   (10.d.e.f)

I want to set the DISPLAY variable on work_linux_box to display on 
Xserver_machine to assist me doing off hours support.  It will be difficult to 
get the comany to modify the firewall.  

So, is this possible to do?  If so, what exactly do I need to do on the linux 
side.  I do have it setup that I can ssh from work_linux_box to ipmasq_machine 
and from there to anywhere on the 192.168 lan.  So I have that much 
connectivity setup.

Thanks for any help, and feel free to ask if more information is needed (the 
real internet ip's will NOT be supplied to help prevent attacks against me or 
my work).

Thanks,

maillst