setting the bit rate

[Jones MB]

is it recommended practice to manually set the bit rate of a wireless 
card?  in the startup scripts I have specified "auto" for the bit 
rate.  when I run iwconfig on the interface, I see that it connects at 
2Mbps.  when I run "iwconfig eth3 rate 11M" the rate does not change from 
2Mbps.

I recently did a kernel upgrade (2.4.7 to 2.4.18).  The driver was upgraded 
from 0.07 to 0.12b.  Before the upgrade I was able to change the 
speed.  Does the newer version of the driver/kernel prevent rate changes 
with iwconfig?

The Linux system has a Lucent silver card with firmware 7.28.  The 
orinoco_cs driver is 0.12b.  The Linux system talks to an iBook with an 
Airport card.  The iBook is running OS X.  The two systems communicate in 
Ad-hoc mode.  There is no AP.  The PCMCIA stuff is 3.1.22.  WEP is off.

Everything works (albeit slower than I would like it to) and has been 
working for years.  I am just trying to make it work a little quicker.

thanks
jmb