Micco,
In answer to your question regarding connection of a USB Zip Drive, the USB interface card for the 9000/Pro does not give you the same type of interface the SCSI port does. The USB interface only gives your PC access to your 9000's internal HD. Where as your SCSI interface gives your 9000 access to a remote drive.
In the future, maybe Yamaha could create an OS Upgrade that would allow the 9000 to remote access a drive via the USB port.
Hope this helps,

Regards,
Dennis Almond