DUMMYNET pipe lifetime

[Ganbold]

Hi,

I'm using DUMMYNET pipes for bandwidth management in FreeBSD 5.2-current.
When I change dummynet pipe bandwidth and then when I try to view it using:

ipfw pipe show

It shows old bandwidth values.
I wander how I can immediately see the bandwidth changes. Is there any 
timing issue in dummynet?
What should I do in order to bandwidth changes occur immediately?

tia,

Ganbold