cdrom and dvd (migrating from woody)

[Nick]

I made an upgrade from a clean debian/woody 3.0 install (no tasksel, no
dselect; change sources.list to ubuntu; apt-get install linux-686;
reboot; apt-get dist-upgrade; reboot; apt-get install ubuntu-base
ubuntu-desktop)

Everything work fine ...except: in /dev there is neither hdc (cdrom) nor
hdd (dvd).

I understand that from woody to ubuntu there is the new "udev"; but the
faq wiki page is  not very informative... and other documents I found on
the subject are realy too technical for me.

Another information: udev seems to work with usb, as it
creates /dev/sda1 a soon as I plug in the usb-disk-pen.

In /sys I was not able to spot any entry related to hdc or hdd

The kernel seems to see them:
...
hdc: SAMSUNG CD-ROM SC-152C, ATAPI CD/DVD-ROM drive
...
hdd: Pioneer DVD-ROM ATAPIModel DVD-105S 011, ATAPI CD/DVD-ROM drive

What do I have to do to obtain back my cdrom and dvd drives?

Thanks

-- Nick