RF and TV Input

Can the aftermarket remotes also access the menu portion of the TV as well as the TV Inputs. The Directv remote has the TV Input button but doesn't work w/ my Panisonic Plasma...unless it is me.

Also where can I get an RF Antenna for my HR21-100 or is it built in? It came w/ an RF Remote.

Thanks

Yes, most of the good ones can do all buttons by learning them...and if you would like the rf option, here is a very good remote system for a very good price.
http://www.amazon.com/RFS200-PowerPak-Bundle-MasterControl-PowerBlaster/dp/B000FL9E6U/ref=pd_cp_e_0/105-2283364-0921258?pf_rd_m=ATVPDKIKX0DER&pf_rd_s=center-41&pf_rd_r=0WXNECT7SKR1N3ZG2ANC&pf_rd_t=201&pf_rd_p=413863501&pf_rd_i=B000GUFX4C

Most any Universal remote would do what you want. I really like the Harmony brand of remotes as you set them up on the internet, plug it in to your computer and everything gets downloaded to the remote. It handles all of the functions of your original remotes. Sams Club has the Harmony 659 for $69.