The ymsgr
in the link is a predefined protocol on your PC. Just like http
, https
and ftp
are protocols known to your system. If you want to create custom protocols to be handled by the pc of your visitor, you must have them install something that will add the protocol to the system. Only then will the pc know what to start.
A good example of a non-standard installed protocol is skype
. The links to add a user to your skype or chat with them only works if the visiting person has Skype installed. Otherwise an error occurs on the computer; "I don't know this protocol, what to do?"
So using a header to replicate the link will not work. Simply because your PC will not understand a header; it will only understand links to protocols, as if you are opening a page (http,https), email application (mailto), ftp programme (filezilla, unless handled by browser) etc etc.