Updating a Vista Credential Tile with a timer

I've been working on a Credential Provider to replace functionality that was
formerly part of a custom GINA in XP. Previously, the GINA would occasionally
check to see if the machine was reserved, and if so would change its UI
appropriately. I am trying to figure out how to get this functionality into a
Vista Credential Provider.

So far, it isn't looking good. From what I've seen, LogonUI will only allow
a Credential Tile to update its UI when it "Advises" it, which only happens
on user-driven events. Am I correct in thinking that this means I can't
update the tile based on some sort of timer? Or is there some way to do this
that I'm not aware of?

The only other idea I have is to put all of the UI that would change on a
timer in a separate dialog, and float this dialog off to the side of the
credential tile. The dialog would have its own separate timer thread to keep
it updated. I'd prefer to avoid such a hackish solution, but I'm not sure I
have a choice (assuming it's feasible... is it?).

Thanks in advance for any advice!