udev does not create /dev/serial

Hello,

to distinguish between /dev/ttyUSBx devices, I saw on collegues laptop that het has a /dev/serial/by-id folder. On my laptop, this folder is not created. I'm running version 151 of udev (my colleage is running 175).

I saw in the udev changelog that this functionality should be there since version 136. What could be wrong? Should I enable this functionality in the config file. We also diffed the /etc/udev/udev.conf and the rules.d folder and nothing seems to indicate why it works on his machine and not on mine. I'm running Ubuntu 10.04 (lucid).

thx for your help,

dvrslype