asterisk users - Oct 2006 - Problem: Dial command with L option

Hi,

I am using Dial command with L option as follow.
L(150000:120000)
The function works well in normal call (IP phone -> PSTN) and the call
dropped when the time is up.  However, it doesn't work in forward
case, (IP phone1 -> IP phone 2 (forward to) -> PSTN).  In the forward
case, there is no warning message and the call will be kept even the
time is up.
Below is what I use to handle the forward with no answer.
exten => s-NOANSWER,22,Dial(Local/1234|30|L(150000:120000))

Anyone has the same experience?   Is it possible to solve it, how?
Thanks.
unplug