I dont believe you can learn any RF commands for your DTV. That being said all the usual suspects will alow for RF commands to some components and IR to others. given your circumstances that really you are only lacking control of your AVR when the doors are closed, you could simply get an IR Repeater system for a relatively cheap price that would allow you to pass the IR signal through your cabinet doors. so in that case you could just stick with your DTV remote!

Good Luck!