Been a very long time user of dd-wrt, switched over to Tomato shibby 1.28 to get some more granular logging of specific IP traffic. I've run in to the exact same problem I had on dd-wrt.
I have ssid #1 handing out IPs in the range 192.168.1.x on br0, ssid #2 handing out IPs in the range of 192.168.2.x on br1 so that devices on ssid #1 are separated from devices on ssid #2. I can see all IP traffic thruput info for ssid #1 on br0, but even though all the IPs are listed in the real time traffic info for ssid #2 and I know devices are connected to ssid #2, they all show 0 total thruput and traffic. I assume it has something to do with the fact that my primary ssid is on eth1 (wl0) while the second ssid is on wl0.1 since it's virtual, but I have no idea how to see the traffic on the second ssid. Any help is greatly appreciated!