Announce mode - simular to MaintenanceMode

Hi folks

First i would like to say thanks to the developers of RT.
That said I would like to use some more knowledge of you experts.

What i’m looking for is something similar to Maintenance Mode
(http://wiki.bestpractical.com/view/MaintenanceMode) but not lock the
access to the RT SelfService.

I’ll explain an example to give you a picture what i want.
If my mail server goes down i would like to tell users that come to RT
SelfService to open tickets that my mail server is down and will come up
again in probably XX minutes or at defined time avoiding users to open
tickets about mail failure. The users see the message and after a few
seconds they are redirected to the RT SelfService allowing them to open
tickets normally.

Can someone point me some wiki or link to where i can read further to
achieve this?

Thanks in advance.

Elton S. Fenner,
Analista de Rede,
Assembl�ia Legislativa do RS.
+55 51 3210-1249