What permission do you set up on the shares?
Is your problem still with permissions? Or you cannot login?
Sounds like you are not giving user and group access through the web interface maybe? I had ran into that issue in the past. I attached a picture, I apologize it is not in German!
Also are you having issues with files on the drive from past installations? Could be your permissions are no good. From command line on OMV, chown root:users /path/to/share should give permissions to any OMV users you create, assuming you have simple ACL/default permissions set up. All users created through webui should exist in 'users' group....
Your mounted drives will be located in /srv directory, if you are not familiar with linux command line the basic directory commands are:
ls /path/to/directory - give simple file listing of directory
ls -la /path/to/directory - give relevant information about directory with permissions and ownership infos
cd /path/to/directory - make target directory the current working directory (then you can reference files directly "file1.jpg" instead of "/path/to/directory/file1.jpg"
chmod 755 /path/to/directory - this is most appropriate in my mind for directory permissions,
chmod 644 /path/to/directory/file1.jpg - this is most appropriate in my mind for file permissions
chmod 644 -R /path/to/directory - this applies 644 permissions recursively, eg, to the directory itself and all files/directories contained within that directory
chown root:users /path/to/directory - this gives user ownership to root users and group ownership to users in group named 'users' to the given directory