I was looking for the USB compatibility matrix in this document: http://www.cisco.com/en/US/docs/video/digital_media_systems/dms_compat.html
and i can see that is not updated ( latest version in the document is 5.1)
Are you aware of any updated version of this document?
In addition, i 'm mostly interested on the usb flash keys i can use in v5.2 . Have you tried any apart from the ones in the compatibility table?