Please note that vpnc.org does NOT certify that products interoperate with each other, merely that they were able to establish a session to an OpenBSD IPSec device. From their web site:
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It is important to note that the conformance tests do not test for interoperability. The conformance logos indicate that the product that got the logo was tested against two different servers, and it passed the test on each server. Thus, the logo indicates that the product interoperates with the servers against which they were tested, but not necessarily with other products that have the same logo.
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Having said that, this has never been tested and from past experience, simply does not work. If you have a VPN3000 you'll save a lot of time by just using the Cisco VPN Client. Sorry.