[CentOS-mirror] Stupid Fastestmirror Update Repo Question

I just double-checked http://mirror-status.centos.org/, which shows ftp.usf.edu as green and 12 hours old, but when we do http://mirrorlist.centos.org/?release=5&arch=i386&repo=updates we don't show up at all and all of our local clients go off-site. How is the mirrorlist populated, and what do I need to do to show up in the updates repos properly again?

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Toivo Voll
University of South Florida
Academic Computing
Data Network Management