redirect POSTs to HTTPS?

Sure! For this you'd use the HTTP::method command. If you just want to redirect all posts then it'd be a pretty simple logical check:

 
 when HTTP_REQUEST { 
   if { [HTTP::method] eq "POST" } { 
     HTTP::redirect "http://[HTTP::host][HTTP::uri]" 
   } 
 } 
 

That's assuming that you want to keep the destination host and URI the same, of course.

Colin