Since Cisco has now known about this issue for 3 weeks, and has failed to correct it, I though I would post it here to warn everybody.
I setup my router (WRVS4400N v2 with latest version 220.127.116.11 firmware) with the intention to create one SSID with tight security that has access to the server's on my LAN, and anothert SSID for public access that has access to internet only. I configured the device with IPV6 TURNED OFF, with all the proper SSID and VLAN settings. Upon initial testing, the Public SSID appeared to function the way I wanted. I could access the internet, but was not able to access or even ping anything on my LAN. Then a co-worker with a new laptop running Windows7 showed me that he was able to browse my LAN and access my Windows SBS 2008 Server when connected to the Public SSID. At first I thought "How can this be". Upon further inspection we discovered that his laptop running IPv4 and IPv6 was able to connect to my 2008 server also running IP4 and 6. Turns out, the VLAN is not filtering out IP6 traffic at all, only IP4 traffic! I created a support incident with Cisco. I sent them my config file. After a few days, they confirmed that they were able to duplicate the issue, and confirmed this is a flaw with the way their VLAN is handling IPv6 in relation to the multi-SSID function.
To my supprise, they responded back that mine was they only complaint they got regarding this, so the issue would just have to wait untill the next regualrly scheduled maintenance firmware release. There would be no raising of priority to resolve this serious security flaw.
I gave Cisco three weeks, now I am posting here to warn everybody.