You need a zero-dollar authorization with AVS - Authorize.net may not support this, but it couldn't hurt to ask.

A large company I worked for in the past (very high volume, high fraud incidence) was able to find a processor and work out a zero dollar authorization w/capture.

I do not have the name of the processor or any of the details of the technical implementation though I can say that this solution does exist.

Try asking around with different processors.

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Dan LeFree | Product Manager (Linux VPS Hosting) | Owner/Operator (Web development, marketing)