Setting up Sonicpoints

Have a location that has a sonicwall controlling 6 sonicpoints ap's.  They are installing a web filter (iprism) to block access to certain sites and run reporting.  The problem is that with the current setup, the sonicwall wireless clients aren't getting filtered.  The filter is deployed "inline" (switch->web filter->sonicwall).  The filter vendor said that since the wireless subnet isn't connected physically to the network, traffic can't be filtered unless we put the filter outside the firewall (which then you lose AD integration, etc).  

Is there a way to set up the sonicpoints where they would be connected to the physical network and be able to be filtered?  I was thinking of buying another sonicwall just to act as the wireless controller and put it behind the existing firewall but that seems like overkill.