Rivello:
Nice! It's a good idea, I think I'll do the same. With a "signal recorder" it would work with any gate, regardless of the control.
Yes you can analyze different signals, even from other stuff, like infrared remotes (haven't worked much on those, but the principle is the same, only they use light instead of radio, and lower frequencies). At some i point i'd also like to integrate my air conditioning in this project too, but that will take quite some time, since air conditioning codes are quite more complex.
About the relay stuff... Thanks for the link, but my problem is not with the relay coil. The problem is the actual motor that the relay is controlling... The same thing that happens in the relay coil, and we fix with the diode, also happens with motors, but is much stronger (since it's a 120W motor). In this case it's strong enough to meld the contacts together, and the relay stays on all the time :s The idea is to make a filter to compensate the effect of the motor, but i don't even have the specs of the motor, which unfortunately is making things harder. 
(You might also want to warn on your site for people to be careful when doing stuff with 220V motors 