Ah, I see - if you want
[PC] -> [Router#1] -> Internet -> [Router#2] -> DOSP
Then you'll need to set:
1) in DOSP, make sure Gateway is Router#2 - nothing related to Router #1 or PC. Technically, when packets arrive at DOSP, it will LOOK LIKE Router #1 is talking! (This is part of NAT function). So even if your PC has IP 192.168.1.20 and DOSP has IP 192.168.1.50, it will not be 192.168.1.20 talking to DOSP, but your ISP's IP such as 220.127.116.11.
2) In router #2, you'll need to set up the IP forwarding (also called Port Forwarding or Applications/Games). If the DOSP has the IP 192.168.1.50, then you should forward TCP ports 80 (web), 771 (RealPort) and 2101 (TCP Sockets) to that IP.
3) Of course in the remote PC you need to point your tools at the ISP's IP for Router #2. So PC think it is talking to Router #2 and DOSP thinks it is talking to ROuter #1 - strange world of NAT
4) if your Routers have dynamic IP (most likely do), take a look at www.dyndns.org to set up a free DNS name for yourself