Bill - Many thanks for the advice. Your suggetion to "insert another device to forward the traffic" looks like a good idea. For example I am thinking of using a second router as a repeater/access point connecting to a static IP through the first/main router - would that work? My connection would be :
Roku -> Router2 (as a repearter connecting to a static IP) -> Router1 (DHCP through my ISP) -> Internet (link to static IP server)
If this might work, then I would pay for a static IP to try this out.
Thanks once again.