Firewall/NAT

I have the latest version of m0n0wall running on a Soekris net4801.

I have 13 static IP addresses from my ISP.  My LAN is setup as a 192.168.1.0/24 subnet and a DMZ setup as a 192.168.2.0/24 subnet.

I setup 1:1 NAT for my public IP's to the DMZ IP's and created some rules to allow http, https, smtp, pop3, ssh.

My problem now is that I can't figure out how to setup a NAT or rule which will allow me to Remote Desktop into my workstation on the LAN subnet (it's using a fixed IP address of 192.168.1.2).  Whenver I try and create a NAT, it says I can't use the WAN's IP address.  I can't afford to use one of my other public IP addresses just to get to my workstation on the LAN occasionally.

Is there some other way I am missing?

Monowall won't let you configure inbound NAT( PAT) for this incoming traffic (using the WAN IP)?  I have yet to get my hands on a monowall firewall (still waiting for my WRAP hardware to make it over here to Iraq), but I'd think this would be fairly straightforward.

From the screenshots, it doesn't look like configuring inbound NAT even requires the definition of an external IP (as it likely assumes the WAN interface IP).  Someone tell me if I am all wet. 

You can use the WAN IP. What's the specific rule you're trying to add, and the exact error message you're getting?