To have DWG documents load fine in Vault, you must uncheck the option called Disable Check In of Design Files.
This option allows user to check in/check out design documents (i.e. dwg, SOLIDWORKS files... other CAD files) within vault out WITHOUT using plugin installed in the CAD application.
Since HyDraw CAD at present has no Vault Add-in, it's the only way you have to manage that file directly within Vault Client and not using AutoCAD.
The video displays the DWG file uploading to Italian version of Vault: