You should be able to locate external SCSI CD burners at places like eBay.
A random search also resulted in the following internal CD-R writer:
http://eshop.macsales.com/item/Hewlett%20Packard/C6020I/
(but do verify the system requirements for CD-burning).
Which operating system is running on the 8100AV? One problem could be to find the necessary software. Before buying anything, ensure that an appropriate (old) version of a burning application is available for your machine.
You may also want to ask the service bureau why they are not accepting your Zip disks. If the problem merely is that they do not have a suitable/working Zip drive any more, one alternative could possibly be for you to provide them with a separate USB Zip drive (capable of reading the same type of disks that you are using in the SCSI Zip drive).
BTW, do you have access to any other computers (Mac or PC)?
Jan