[Samba] azure AD Connect | passwords not syncing

[mj]

Hi,

We setup the microsoft azure AD Connect on a windows 2012 server, to 
start using (testing) office 365 in the future. We're running a samba 
4.4.4 AD.

This all worked, in the portal.office.com admin section we can see that:

> Company Name 	COMPANY
> Domains verified 			2
> Domains not verified 			1
> Directory sync enabled 		true
> Last directory sync 			last synced 3 minutes ago
> Password sync enabled 		true
> Last password sync 	
> Directory sync client version 	1.1.281.0
> IdFix Tool 	Download IdFix Tool
> Directory sync service account 	Sync_WIN2012-PROXMOX_63nfmdcompany.onmicrosoft.com

As you can see, the sync seems to work, however: "Last password sync" 
field is empty, even though the password sync functionality IS enabled.

There don't seem to be any errors, and I can see all our AD accounts in 
the office365 web interface.

In all online examples/howto's, the "last password sync" is never empty, 
so our status seems to be irregular.

Before looking into all kinds of details, the basic question first:

Is password sync using Azure Connect to the azure cloud supposed to 
work? Does it work for others here?
Anything special that needs to be done/taken care of on the samba side 
of things?

Best,
MJ