The bridging option under the wireless section is NOT the bridge mode option I was referring to. That's wireless bridging based on WDS (Wireless Distribution System), which allows the AP to associate with another WDS-enabled AP. The bridge mode I'm referring to changes how the modem+router handles the connection from the ISP. In bridge mode, the modem+router would disable all its routing functions and pass the public IP directly to the WAN port of your old router. But after quickly skimming the manual, it doesn't appear to be an option (at least I couldn't find it).
http://www.cisco.com/en/US/docs/video/a ... 6168_A.pdf(assuming I have the right device)