monitor power down when x starts using kvm switch

[Bridge]

Ciao guys,
i'm having a problem with a kvm switch, model Aten MasterView cs-82a.
I start the machine connected to the screen via kvm, it seems to work 
and  i can see the boot.
However as soon as X starts the monitor makes a couple of flashes and 
goes to sleep.

This is really odd since if i press ctrl+alt+f1 it turns back on and i 
can use the shell, however if i ctrl+alt+f7 it shuts down again!

Someone on the irc channel kindly suggested that this has to deal with 
the EDID signal and my nvidia driver autosetup.
i added the following lines to my xorg.conf

(monitor section)
Option         "NoDCC" "True"
Option         "UseEDID" "False"
HorizSync       30.0 - 81.0
VertRefresh     56.0 - 75.0
(screen section)
#Option         "MetaModes" "nvidia-auto-select, nvidia-auto-select"

the complete xorg.conf is avaliable at:
http://atelier.inf.unisi.ch/~primim/VAR/xorg.conf.txt

This configuration works without the switch but when it is connected 
nothing changes, same behavior as before.

here you can find a log of a cold boot with the kvm attached
http://atelier.inf.unisi.ch/~primim/VAR/Xorg.0.log.txt

 From the log it seems to work fine, in fact if i take out the kvm with 
the pc on, and i connect the monitor directly it  wakes up and works.

what else can i try?

Ciao
Marco