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As far as I know you don't have any possibility to cripple the immobilizer by using a normal VAG COM version. But there are possibilities to handle this problem. First of all you could try to get the original carkey, the ignition lock and the immobilizer induction part. But I think this can lead to other problems.
Another idea is to find out somebody who is able to cripple the immo. I just used google an find this page gti-tdi.de and he says that he is able to do what you need. Perhaps you will get more information by sending him an email?
Matthias