help with a USB modem

[Al Stoltz]

Greetings...

My USB modem will not work with the stock Warty 2.6.8 kernel.  When
plugged in, the system recognizes the modem and even loads the correct
module (cdc_acm in my case) but it does not create the device node.
lsusb lists the modem and it shows up in /proc/bus/usb/devices.  I tried
manually making the node /dev/ttyACM0 (that's what I think it should be)
but then pppd spits out an "invalid argument" error when trying to
connect.  I also tried making a udev rule based on the modem serial
number but still no joy.  

I've looked at dmesg and syslog and there doesn't seem to be any hints
at what the problem might be.  Google is also of little help - there are
a few similar problems but no solutions that I can find.

Currently I'm using Ubuntu's 2.6.7 kernel and all is well - even my udev
rule works.  But I'd really like to figure out why it's not working in
2.6.8.  I have a feeling that it's a kernel (or maybe the cdc_acm module
itself) problem but any help would be appreciated.  Thanks.