Yes. However I think having this router and the one thats built into the 2wire is probably causing issues with NAT. This router is unable to translate port and firewall requests and data traffic due to the fact that your 2wire is trying to do the same thing and data is getting lost in translation. This router expects there to be a global port open to translate and manage traffic. The 2wire modem/router is doing this already on it's WAN side, and probably handing off a private IP address to the 655 router in which the global ports are not available to use on the 655 WAN side to LAN side. Thus you port numbers you've entered in on the 655 are not getting out past the 2wire modem/router. How many LAN ports are on the 2wire modem besides the WAN port? 4 or just one? If only one, then you could put in place a switch to connect additional wired devices instead of using an external router.
I would recommend you connect your PC and/or the server directly to the ISM Modem/Router by passing the 655 router and you'll probably get port numbers working correctly. IF this is the case then, in some cases ISP modems can be bridged to effectively turn off the router portion of the modem, thus making it a stand alone modem and handing off a public IP address and global port function to the 655 router and thus all port forwarding functions will be handled on the 655 router correctly and no the ISP Modem. Be ware that some modem/routers can't be bridged.
You can check to see if the 655 is getting a private or public IP address by going to Status/Device Info/Wan section. If you see a 192.168, 10.0 or a 172 address for the WAN IP address, it's getting a private IP address. Preferred is: ##.##.###.### something starting with a 2 digit number, not 192.