@Kinster: you don't need this interface to have two HDDs on the IDE bus.
@Animagic & Framiga: do you use scsi.device or atapi.device in your DosDriver ? Atapi.device is part of the IDEfix package. Did you delete atapi.device (and every other file that has atapi in its name from Devs:) and does the CD-ROM still work ? AFAIK scsi.device (the only part which comes with OS3.9) does *not* see the second channel unless it is patched by IDEfix.
Bye,
Thomas