Windows 8 uses SMB version 3, most devices are built on SMB version 1 and 2. Version 3 is supposed to be backwards compatible, however most devices running versions 1 and 2 don't have that functionality enabled, or do not understand the newer protocol entirely.
Many copier vendors do not have a solution for this yet. Both Ricoh and Toshiba are not scheduled for a solution until Jan 2013.
Ricoh Problem Bulletin #TS121417 dated Oct 2012 confirms the same.
Scan to FTP, Scan to Email and Scan to USB are current solutions that should work.