[CentOS] Munin issue

Hey Guys, I am trying to wrap some loose ends up before we close tomorrow and have one last thing. I have been asked to monitor tunnel bandwidth for vpn clients over the holidays and whipped up a quick Munin plugin to do this. It works well but one problem is that when a client disconnects, the plugin stops submitting graph data for it, so the png's don't show the user anymore, kinda hard to see what's been done over the time period they "were" connected.

How can I tell Munin to retain the data it has seen? I would rather this approach then hardcode the users in, as I have to manually maintain that list then...

Thanks! jlc