I did a little research on the single button immobilisers. If your immobiliser is a VIM172, it is basically the same unit as the various otherr Bosch single button systems used by Porsche, Ford and GM Europe. I found on a Ford site some instructions on bypassing the Ford VIM125/VIM179, which may work on the Ferrari immobiliser, but since I have not tried, I do not know for certain. I was keeping them in case I needed them some day; if you send me a PM with an e-mail I will send you the .doc files I have. They might help.
'97 Rosso Corsa 550 Maranello