You might have to speak to microtek which is a pain since they are in taiwan
but there is a contact page here
do you know what the other cables are for ? Do they go to an automatic document feeder ?
if so you might find something on ebay
this page has a bunch of adf cables, I dont see the ones for that model but one of the companies on the page might make it
They may also be connectors for different types of interfaces and would not be necessary just the power and usb cable are the only ones you really need unless one connects the ADF unit.
The power cable may be a standard power cable. Does it look like this