"usb charging drivers?"
There are no need for USB drivers to charge..
But if you still want the drivers for using the other external software i.e Pc Studio...
It (the Reality) doesn't work well with Bitpm yet... I'll give you the links below..
http://www.vzam.net/or
http://www.vzam.net/download/supported.aspx <----- just pick the file for the u960...