I haven't really tried your setup with the LDAP binding, but some things should work nevertheless.
1) Create a NFS-Share on your freenas server, that you want to be accessed through UCS. I've changed the permissions in freenas (dataset and share!) to the Univention user mounting the drives/shares.
2) Create a share on Univention master:
- domain -> shares.
- As you created freenas as a member server, you can select it from the dropdown menu.
- The path is the full /mnt/... path in freenas.
- Select user and group the same as on freenas
3) On Univention master:
- Select the Univention device -> computer, where you want to mount the share.
- Go to the policy tab -> NFS-shares, create a policy. You can of course and perhaps for better create the policy before this... (domain -> policies) Select the share from dropdown, enter the path where you want to mount the share.
4) perhaps a reboot is needed, but I'm not sure.
But what about smb-shares???
The step 2 from above, domain -> shares - you can chose if you want to enable the share as samba/nfs. The above guide is working with nfs. (I use a setup like this for mounting bareos-storage to Univention)
If you want to use the freenas-share for the user-accounts over smb, then you want to enable both, samba and nfs and perhaps adjust the permissions.
I don't know, if you can connect directly to freenas smb-shares from a joined windows computer with the LDAP setup. It's possible with the AD binding in freenas. If you can, then you don't have to mount the share locally to use it in the user accounts and point to freenas there.