First thank you for the repplies.
Yes. I tried a different radio (the one who drives the display
"crazy") and the radio is working perfectly. So the bad connection/
antenna probles are ruled out.
And the radio when I start the car in the morning is working fine.
After 10 to 15 minutes the problem starts and I can only receive noise
(no matter which frequency is tuned). After switching off for 2 hours,
it starts working again!
I assume one electronic component have a thermal failure.
I will try the switch off the battery trick to see if the car
recognise the used radio.
What I really like to know is if there is a way to have the controls
back in the steering wheel and the central display working.
BTW and as a side note, I've contacted Clarion portuguese
representatives (I live in Portugal) and they don't give technical
support/repair to those models made for auto manufacturers!!! Is that
normal?

Err, most people would suggest disconnecting the battery before
changing the radio or delving into a dashboard assembly...

Anyway, the above problem has made be remember of a fault I once had
to trace on a Fiat were similar "The dashboard has gone mad" problem
had occoured, turned out to be a missing ground (earth) wire for the
main processing unit, once the unit was correctly grounded everything
went back to normal.