asterisk users - Jun 2005 - How to detect telco Message Waiting Indicator (WMI)

I'd like to be able to configure Asterisk to detect and respond to message
waiting indications from my telco, as I'm using the telco voicemail as a
fallback in case the Asterisk line is busy, Asterisk or it's server is down,
etc.  Detecting either the FSK (preferred) or the stutter-tone, would allow
Asterisk to notify me that there it missed a message.  I see periodic
queries about this, but haven't found anyone who has solved it.  Are there
any answers out there?  I'm using a TDM400P.

         -Brian