[ns] How to change parameters via TCL file in 802.11e TKN model

[hirantha]

Hi all,
 I'm using 802.11e TKN model and I just want to know the way to change 
the parameters (e.g. AIFS, TXOP, CW_MIN, etc) via TCL file. I tried as 
follows 
but didn't work. 
  $opt(ifq-bs) Prio 0 CW_MIN 31
 
 If anyone knows the way please reply me. Thanks in advance.

Sithira