Its possible (depending on several factors).
1) From Home: Home 5x, FF, PP, RW, PP, FF (takes you to the Platform Secret Screen)
2) Select "RF Remote Menu"
3) Select "IR Transmit Menu"
4) Select "Enable Querying AVRs (instead of TVs)"
5) Go Home/Settings/Remotes & devices/Remotes/<your remote name> (in use)/Set up remote for TV control
You may have to go through many codes, and if you get the "try again" (if you answer yes to the first question, and no repeatedly until you get the "try again" dialog box), you can manually enter brand names to try codes from.