All of the Linksys and Netgear Cable / DSL routers can be managed. The 'proper' way to handle this would be to configure everything using your external IP address, then set up a routing rule to allow bouncing between private ip space and public ip space so you can also connect.
It's not too strange and I bet if you try the forums at
http://www.dslreports.com/ you can find someone to help for your specific router.