Yaris 2007 remote entry doesn't open (it only closes)

[nicorac]

Hello everyone, I'm experiencing a strange issue with my Yaris 2007 remote entry control; maybe someone could share some light on it.
Sorry for my bad "technical" english (hope I'm using the right terms).

The issue is this: on the remote entry control only the Lock button works, Unlock does nothing.

Details:

• Yaris 2007
• one key with 2 buttons embedded remote (Lock/Unlock) + transponder
• another key with transponder only (no buttons at all)

Tests I've done:

• all the doors Lock/Unlock using the internal switch (the one on driver door panel), so I exclude fuse or cabling problems
• all the doors Lock/Unlock using the mechanical key (outside the driver door)
• all the doors Lock by pressing the remote Lock button (even far away from the car) and the red LED on the key lights up, so I exclude remote battery problem and radio issues
• pressing remote Unlock button does nothing (I hear no noise at all) BUT the red LED on the key lights up, so I exclude the button itself is broken

I tried to re-add the remote following the procedure here (http://www.yarisworld.com/forums/showthread.php?t=20865), but nothing changed.
To confirm I followed the steps correctly I also tried to remove all registered remotes; after that the remote was fully nonfunctional.
Then I re-added it, but I still have the same issue: Lock button works but Unlock not (LED key lights up with both buttons).

Hope someone could help me, I'm getting crazy