secure sql 2008 r2 backups

Hello, I've read through this

http://technet.microsoft.com/en-us/library/ms190964(v=sql.105).aspx

and besides managing AD accounts ACL I don't see anything else to protect sql backups. On Enterprise Edition TDE. Anything else? What's out there for future editions? Anything new? I believe for 2012 only TDE as well.

Thanks

Paula