The links to the programmer's guide for VDDK 5.0 have been broken since it was release, any chance we could get a peek at the updated programmer's guide?
http://pubs.vmware.com/vsphere-50/topic/com.vmware.vddk.pg.doc_50/vddkPreface.html
http://pubs.vmware.com/vsphere-50/topic/com.vmware.ICbase/PDF/vddk_prog_guide.pdf
http://pubs.vmware.com/vsphere-50/topic/com.vmware.vddk.utils.doc_50/diskutils_preface.html
http://pubs.vmware.com/vsphere-50/topic/com.vmware.ICbase/PDF/vddk_disk_utils.pdf