It is recommended as a best practice, that you backup the virtual guest, and then have a 2nd job with an agent to backup just AD, or Exchange, or SQL.
The virtual guest backup via hyper-v or vmware for that matter, will not truncate the logs for exchange or sql.
A new cool feature of BE2010 is GRT aware backups in Vmware, not sure about Hyper-V though... Backup the VMDK, and it can recover files, folders, AD objects, Exch info, and Sharepoint docs, all from that single VMDK backup! Wicked cool.