For those of you who use xen4centos, but are not on the centos-virt mail list (shame on you if you do that :D) ..
http://lists.centos.org/pipermail/centos-virt/2014-October/004132.html
If you can test the auto update functionality of the kernel as outlined in that post and report the results (hopefully to the virt mail list :D), it would be greatly appreciated.
Thanks, Johnny Hughes