iRule to display remote content through fake URI

To expand on Ed's description

One way you could do this is to create pool pointing to the IP address for https://helpsite/help. In my example let's called it pool_helpsite.

Once that is created you would use the following irule

when HTTP_REQUEST {
   switch -glob [string to lower [HTTP::uri]
   "/help"-
   "/help/"  {  
HTTP::header replace Location "https://helpsite.com/help"
 Pool pool_helpsite
snat automap
}
   }
}

The snat command basically ensures asynchronise routes to devices in a pool where they are not the gateway.

I hope this helps

Bhattman