iRule Help selecting pool and SNAT_pool for specific URI's

We have an existing virutal server that we are trying to redirect traffic to different pools based on the URI requested. The iRule I have set up is below. The problem is that whenever a request for /a/* is sent the appropriate SNAT_pool and server pool are selected. However whenever a request for /TrafficDirector/* is sent the appropriate SNAT_pool is selected but the server pool the request is sent to is the default server pool. See below for the iRule:

when HTTP_REQUEST {
  switch -glob [ string tolower [HTTP::path]] {
    "/a/*" -
    "/TrafficDirector/*"
   {
       Select the corresponding pool and SNAT pool
      pool pandora.dev.foo.net_Inside_ProxyServers
      snatpool blockbrochure-dev.stackato-1.foo.com_SNATpool
      return
    }
    default {
       Select the default pool 
      pool dev.foo.com_pool
    }
  }
}

What am I missing here?