The overall issue of multi-function-printers not being able to scan to an SMB share on a Mac server relates to when Apple switched to using their own SMB software called SMBx instead of the previously used open-source Samba software.
This change was caused by the Samba project moving to a GPL3 type license which Apple felt they could not agree to. Apple made the switch when they released Lion aka. OS X 10.7. Prior to that Apple had stuck with an older version of Samba under the GPL2 license but had fallen further and further behind the current Samba versions as a result.
With SMBx Apple wrote their own solution from scratch and was able to add new features like compatibility with SMB2 which newer versions of Samba are also compatible with. However Apple did also fail to implement some other features. One of these was the ability to act as an NT style Primary Domain Controller (PDC) or even a Backup Domain Controller, and similar older less secure types of Window authentication also got lost. It is these losses that caused most of the compaibility problems with MFP scanner type devices although the SMB2 vs. SMB1 difference has also had some impact.
Apple has gradually improved things but overall the situation remains unchanged even with Mavericks, however it is also the case that makers of MFP devices have now been aware of this situation for some time and some of them have issued new firmware to get round these issues.
Therefore you should see if there are any new firmware updates for your MFP that may help or the only other options are as follows -
- Use a different protocol, some MFPs support FTP and/or email as options and yes particularly with FTP there are security concerns
- or use a different server for the SMB share, this could even by a virtual machine (running on a Mac) using a shared folder on the Mac and then serving it via Samba or of course you could use a 'real' Windows server
- or you could look at installing yourself the Samba software on the Mac and 'replacing' Apple's SMBx software, see SMBup at http://eduo.info/apps/smbup