http header inserts

I need the following irules to erase the icomming header and then insert.

 

 

when HTTP_REQUEST {

 

if {[HTTP:header]exists remove it and insert the following

 

HTTP::header insert HTTPS off

 

HTTP::header insert X-Forwarded-Proto http

 

 

}

 

 

when HTTPS_REQUEST {

 

if {[HTTPS:header]exists remove it and insert the following

 

HTTP::header insert HTTPS on

 

HTTP::header insert X-Forwarded-Proto https

 

}

 

 

is this do able and if so how ?

 

 

 

Thanks