asterisk users - Jan 2004 - FLASH TONE

Hi list.

   I'm having the next problem. I Bought a new analog phone, it have 
flash button, but it send a tone not a cut on the line.  So the flash 
key is not working, a thing that was problem of the phone, but i connect 
another phone that have the same problem.

   I suppose that the flash key send a tone, becouse when i push it i 
lost the dial tone.

   Any idea how can i do, so * detect that tone as flash key ?

Alvaro Parres