VMware Contributed Sample Code Disclaimer
The attahced sample code shows how to use VDDK to extract disk signature and possibly modify it - both in managed and hosted scenarios.
Hopefully, you will find them useful. Note that this is sample code to show how to work with VDDK and not meant for direct use in your production code.
Sample Code: http://communities.vmware.com/blogs/sudarsan/2009/01/21/new-sample-code-for-vddk