Solved. Got it to work. I changed some files, first in /usr/share/zentyal/stubs/zarafa/server.cfg.mas I changed server_bind to 0.0.0.0 and in ldap.openldap.cfg.mas I changed ldap_nonactive_attribute from empty to zarafaSharedStoreOnly.
Then I changed /usr/share/perl5/EBox/ZarafaLdapUser.pm and /usr/share/zentyal/templates/zarafa/zarafa.mas (see attachments).
I also updated zarafa with the commercial 7.0.1 version as we have a 25 user license directly from Zarafa. And lo and behold, working.