I cannot take to much credit except a link. Do what this guys says and it .  . . works.

http://rathelm.wordpress.com/2012/02/03/cent-os6-2-and-netatalk-2-2-0/

Then all your macs can backup to time machine. Don’t forget to set up a sparse bundle with a fixed size, else it will engulf the whole hard drive choking others out.

I use this in concert with setting up Time Machine to see a network drive instead of a local drive.