Modify an Epson Workforce 645 ADF scanner to accept smaller documents?

Hi,

I've got an Epson Workforce 645, and bought it specifically for its duplex scanning functionality. (Scanning my old books that are now out of print and literally falling apart at the spine...)

However, it turns out that it has a minimum possible size for scanning documents through the ADF.

The page size I'm hoping for is something slightly smaller than A5.

I'm hoping that there might be a hardware fix for this, and was wondering if anybody had any ideas.

Thank you