LARTC - Jan 2008 - why can`t i attach wrr to a htb or hfsc class ?

Attaching WRR to a hfsc ot htb class after a while i will get all
packets drop and syslog full of
HFSC or HTB : Non-work-conserving qdisc

any ideas ?
-- 
[]''s
Salatiel

"O maior prazer do inteligente é bancar o  idiota
   diante de um  idiota que banca o inteligente".