Samba "Share with Account" mixes folders from 2 partitions

[BunchOfSage]

Hi, this is my first posting here,

I contacted ASUS support a few days ago with this issue with my AC56U router:

Hi I'm running firmware 3.0.0.4.374_4561, connected my external usb 2.0 hard drive
to the router and wanted to create a network share drive for Win 8 and Win 7 PC.
There are 2 partitions on that hard drive (1 NTFS, 1 FAT32). Despite having samba
server enabled in the web interface, I had trouble to get the AC56U listed as
"computer" in order to open the file system. In the end I even got samba working
(FTP was working all the time but samba was tricky, cannot reproduce the problem).
But what I find somewhat strange is the following (also see screenshot for further
illustration): when "share without account" is selected, I see both partitions as
expected when entering \\RT-AC56U in the explorer address bar. For security
reasons I then selected "share with account". Now, \\RT-AC56U returns a folder
directory of all folders that I have read/write or read access to. So folders from both
partitions are mixed and displayed. What bothers me: I want to select a certain
partition, right click on it and assign a network share drive letter to it such that it
behaves like a normally mounted partition. This seems impossible when "share with
account" is active.

They replied back (translated from German):

Unfortunately specifications set a limit to just one partition at maximum being detected and used with read/write access.

I am not sure if they really answered my question (and told the truth), since I was very well able to see both partitions with \\RT-AC56U in Windows Explorer when using "share without account". Is there really a limit when "share with account" is active? And if so, why do I then see folders from the other partition, too?

Best,
Hannes