Portion of iRule not being processed

I'm coming back to this after a few days - it appears as though the query is not being changed to lowercase, and doesn't process unless I manually change the TID, FID, or C to lower case. Then, the redirect happens properly.

Here is the iRule in its current state:

 Check the Host header value, set to lowercase

switch -glob [string tolower [HTTP::host]] {
      "oldforum.olddomain.com" {
          Check the URI, set to lowercase
         switch -glob [string tolower [HTTP::query]] {
            "tid=*" {
               log local0. "Query is [HTTP::query]"
               HTTP::redirect "http://newforum.newdomain.com/default.aspx?g=posts&t=[URI::query [HTTP::uri] tid]"
               return
            }
            "fid=*" {
               log local0. "Query is [HTTP::query]"
               HTTP::redirect "http://newforum.newdomain.com/default.aspx?g=topics&f=[URI::query [HTTP::uri] fid]"
               return
            }
            "c=*" {
               log local0. "Query is [HTTP::query]"
               HTTP::redirect "http://newforum.newdomain.com/default.aspx?g=forum&c=[URI::query [HTTP::uri] c]"
               return
            }
         }
      }