Hello,
I have a My Cloud Home disk, from Western Digital. It is not a real NAS solution (as I discovered after non-refundable purchase 
), but it does provide a Public shared folder with SAMBA. Anonymous users are allowed to mount, read and modify smb://xxx.xxx.xxx.xxx/public share. I have installed OMV on a Raspberry PI. I'm trying to mount smb://xxx.xxx.xxx.xxx/public with the Remote Mount plugin and add it as a Shared Folder for SMB and Apple Filling services, and user-based permissions (yes, I am aware the disk is still discoverable on the network as a public share, but the usage of a user account is for convenience: I have other drives I want to share and I would like to reunite everything under the same SMB/Apple Filling server).
System information:
I mount the device using Remote mount, configuration following:
I then create a Shared Folder a set the Privileges
And then configure the Service (SMB/CIFS is providen as an example, most default settings preserved):
At this point, I'm able to discover the SMB/CIFS server on my network, connect with my user account `jean-luc` and see the content of the Shared Drive I created, but the drive is in read-only... I have tried many permutation of the steps explained above, notably attempting to change the ACL with the recursive option enabled: it generated a bunch of Operation not supported setfacl errors.
Note that if I access to the Raspberry PI through SSH and navigate to the folder where the Remote Mount Plugin mounted the drive (under /srv/), I'm able to modify the content of the drive, so it doesn't seems to be mounted as Read-only. I think I'm missing something in the configuration of the Shared Drive, but I have ran out of ideas at this point. I would appreciate your help. 
Please find attached my config.xml (or txt).