Luis,
I would make a backup to desktop or tape. Then image your scsi drive using ghost/g4u/dd/etc (only a precaution). Then pull out the scsi hardware and install a fresh 5.6 to new IDE drive. Perform a restore from backup. Can ghost apply an scsi image back to a IDE????? you might look at this.
If you need things on the old drive, you can always put it into another system and access the data with knoppix or mepis live CD.
Just some thoughts.
ryan