Bidirectional traffic control with PF and altq or dummynet

[eculp at unixmania.com]

I have been using PF for several years now and used IPFW previous to  
PF that I've grown more and more fond of. I now need to manage  
bidirectional traffic  I have used Dummynet before to do similar  
things but it is my understanding that Altq can only manage outgoing  
traffic.

My questions are:

   Am I correct in saying that Altq can not manage bidirectional traffic?

if not

   I understand the dummynet can be used with pf and if so does anyone know
   of a howto to get me started?

Thanks,

ed