If by 'little cylinder' you mean the small glass pill like thing normally tucked in one side...
...then you could be in trouble, it's an RFID transponder (...or similar, not sure exactly the tech) that transmits its unique ID to the ignition system when it's close to the lock. Without a known ID the car won't start.
Best bet would be to try and find it, otherwise I think you have to buy a new one and get the new one's ID programmed into the car at a dealer for some crazy Porsche fee.
Threaded Mode
