Thanks for you reply.
My problem appeared while doing a firmware update. It failed (for no obvious reason) and the drive was detected only as "Initio Default Controller" and nothing else (the drive itself was not recognized). I tried pretty much everything: tested on two sytems (XP and 10 Preview), tried to update the firmware again (drive is not detected) and Googled the problem (how I got here). I came to the conclusion that the failed update broke the controllers firmware and it couldn't access the drive anymore.
I just decided to do some some more searching and I was able to restore the drive by applying
this firmware. After that it updated to the latest firmware from WD's site and is working fine again!
My drive is a Passport Elite 320 GB (WDBAAC3200ACH) by the way.
Also the link to download the "Virtual CD (VCD) Manager for Windows" on your support site is broken.