Volkswagen: Remote Keyless entry, remote keyless entry, vin number

Question
I own a Passat 99 and I have just one regular key. I want to buy another key(with remote buit in from ebay.com) and I don't know which one will work with my car. Do you can help me please. If you need the VIN# let me know and I will send it to you by email.
Thank You for your time.
Mark  

Answer
there are a few problems you may encounter, the remotes frequincy depends on chassis numberfor one. the other problem is that cars which do not have remotelocking will not be able to be converted by simplying buying a fob. certain "base" models do not have it. if you supply me with the vin number and model code, a six digit figure beginning in 3B0 or simular. i will enquire if it is possible. email me direct on john_dempsey82@hotmail.com.