Luis,
I have checked out your problem using a Beovision 1 in a link room and an AVANT as the master with a camcorder connected to the AVANT.
I set up initially a basic configuration on my Beo5 with just the two rooms and added a button for link TV as you stated it and it worked perfectly for me. Both audio and video from the camcorder being feed into the camera socket on the AVANT appeared on the link Beovision 1
I did the same with a more complex Beo5 configuration and it still worked.
So, I can confirm that 1:000:TV:Camcorder using the latest formware 1.34a works correctly, so I can only assume that there is something unique with your Beo5 Configuration.
You may wish to try removing the camcorder button from the configuration, saving the configuration, then putting the camcorder button back.