PSTN line disconnect detection of Brekeke

[Niggy]

1. Brekeke Product Name and version:2 1 1 6

2. Java version:5

3. OS type and the version:xp sp2

4. UA (phone), gateway or other hardware/software involved: x-lite
Grandstream FXO gateway
5. Select your network pattern from http://www.brekeke-sip.com/bbs/network/ ... terns.html :2

6. Your problem:
Hi there,
When i call from land line to a brekeke user & hang up the call, the brekeke user continue ringing for about 20 seconds.
So how to reduce brekeke detection time for (pstn line disconnect) event ?