Fueluser

I have an 07 panel. Has anyone tried using the emergency horn button on the Key fob for something else? Forgive me if this has been covered as I don't search well on this site. What I wanted to do is use that button to pop the drivers side rear door. I know the new panels I believe, have dedicated buttons on the key fob to pop the doors. Would I be able to retrofit my 07 with a new key fob or could I find the emergency horn signal on the fuse box and just move the wire from the dash button to the horn signal link on the fuse box? John