This is an old revision of the document!
http://www.msexchange.org/articles-tutorials/exchange-server-2010/management-administration/resource-mailboxes-exchange-2010-part1.html
http://technet.microsoft.com/en-us/library/bb124952%28v=exchg.141%29.aspx
http://technet.microsoft.com/en-us/library/bb124374%28v=exchg.141%29.aspx