USB mass storage devices use the usb-scsi emulation layer. You might get somewhere with that.
In general, I doubt it; SCSI is more complex than IDE/ATAPI as I understand it, though there is a relationship between the two.
If the application is looking for a /dev/sda file, but treats it as a block device (i.e. it doesn't do any low-level SCSI manipulation of it, like trying to eject it), then you can create a symbolic link instead. As root:
Code:
cd /dev/
rm -f sda
ln -s sda hda2
That will link the /dev/hda2 partition on the first hard disk to the second. This may not work with devfs (a virtual /dev filesystem) but you can do something similar if you're using that (see the devfs documentation). You can also link contiguous files to it. You can create an (e.g.) 2Mb contiguous file with:
Code:
dd if=/dev/zero of=/tmp/contig bs=1024 count=2048
