Dummynet pipes and MRTG

[Ganbold]

Hi,

I need to view the traffic utilization of dummynet pipes in ipfw2. I'm 
using FreeBSD 5.2 current.
I'm also using MRTG to draw graphics from ipfw show rule-number command.
Is there any method or program like MRTG to draw bandwidth utilizations of 
dummynet pipes?
Can I use MRTG for this purpose?
I hope somebody in this list point me to the right direction.

thanks in advance,

Ganbold