multipath path recovery?

Hi all,
I'm investigating an issue on RHEL 6.3. We have SAN disk connected via multiple paths. This all shows good from multipath -ll. When the storage guys remove/disable one of the paths they vanish from multipath -ll. The "problem" comes when they re-enable them, they don't re-appear in the multipath -ll output. The only way to get them to re-appear is to reboot the servers.

Should these paths automatically be recovered, without a reboot?

Some of the other engineers say that is normal. Am I expecting too much from multipath?

Stephen Brooks