Thanks for all your comments, it really encourages me. I didn't even thought of simulating a push of buttons, maybe I'll give it a try!
I think that, at first, I would like to keep my device small, so I guess that just capturing and copying the signals I need would be enough. Actually, I just need power on/off, volume up/down and channel up/down. I'll try spankyham's CRO idea and see what could be done. I'll post an update here when it comes.
Thanks again all!