asterisk users - Aug 2005 - call waiting beep on PSTN and TDM400P FXO line hook flash

I have been looking for the answer to this question for a 
while.  Google-ing and reading the archives of Asterisk-Users has not 
enlightened me.

   It seems that this question has been asked many times, and many times it 
has gone unanswered.

  I have call waiting and three way calling on my PSTN line from Verizon 
(the local telco).  This is connected to a FXO port on a TDM400P.  I also 
have two FXS ports on the TDM400P.

   So my problem is, how do I flash the Verizon PSTN line when I hear the 
call waiting beep?  How can I send a hook flash to the Verizon trunk to 
activate their 3-way calling feature.

   I have seen some stuff like "hook flash then send *0 to get the bridged 
Zap trunk to flash" but I can't get it to work.  I get the reorder 
signal.  I need something my wife and kid can do.

   Can anybody help?

   Thanks,

   Jeff