[Samba] server not using utf8-mode with Synology client

[Xen]

I wrote here how my filenames are getting mangled when getting sent or 
received to the server.

Server: current Ubuntu lookalike.

Client: Older Synology diskstation with probably a modified mount.cifs.

When I send utf-8 it gets received as dos.

"é" for instance is #c3a9 in utf-8, and it is used by the server as #c3, 
#a9, two separate bytes, becoming é.

The server is just configured with defaults for "dos" and "unix" 
clients.

The client tries to use iocharset=utf8.

What can I do to enforce utf8 being recognised by the server?

It apparently thinks it is talking to a dos client.

But unix extensions are being negotiated because the client sees the 
permissions and ownership of the separate files.


Anyone know what to do? Do I need a different mount.cifs?

Regards.