Hook Flash Timing

I know the answer must be around here somewhere, but I cant seem to find it.

I have an asterisk installation 1.2. I have installed 2 x HFC ISDN cards (1 in NE mode and the other in NT mode) And also 2 x TDM400 boards. 1 with 2 FXO modules, and the other with 4 FXS ports. I need to change the flash timing, the american standerd is to long for Europian anolouge phones. The flash/recall button breaks the circuit for more or less the same speed as a pulsed one. Just slightly longer than 100 ms, 200 ms is also common. Pressing the hook switch down for about 400ms works, but not everyone can grasp this concept. I have tried changing values in zapata.conf etc.

Does any one know how I can change this ?

Found this on the wiki but does not say anything about the value I would assume its in milliseconds

debounce: Sets the debounce timing. "The debounce settings in the Asterisk configuration affects how Asterisk
handles hookswitch transitions on its FXO/FXS interfaces