Static URI Rewrites

Our website search functionality has gone through some heavy modifications recently and in doing so, the url's have been completely rewritten.

To give you a better understanding of whats going on, I'll list the old way and the new way.

www.site.com/common/search/searchcombined.asp?category=XXYYZZ

www.site.com/common/search/searchresult.aspx?categoryid=AABBCC

Additionally, we have a static list of mappings between XXYYZZ and AABBCC that I can populate into a list.

I've gone through the boards and put together the following iRule, but its not working.

class CategoryID
{
 "LIGHTING 26"
 "BEDROOM 30"  
}
when HTTP_REQUEST
{
 if {[HTTP::path] == "/searchcombined.asp" }
 {
  set qstring [HTTP::query]
  
  set CategoryID1 [findstr "category=" [HTTP::query] 7 "&"]
  if {$CategoryID1 != ""}
  {
   set CategoryID2 [findclass $CategoryID1 $::CategoryIDs " "]
   if {$CategoryID2 != ""}
   {
    set qstring [string map [list $CategoryID1 $CategoryID2] $qstring]
    
   }
  }
 HTTP::respond 301 Location "http://[HTTP::host]/common/search/SearchResult.aspx$qstring"
 }
}

Any help or suggestions would be great.