Thank you Bob, Daniel
It seems my problem was that I didnt add the lang="fr" to the main xml file.
The documentation is split between many files, all merged together using
<xi:include ...
and I only tried to set the lang paramter to the included xml file.
now I have added it to the main xml and I get correct translations for the
xref string.
im such a noob, im really sorry for bothering you with such issue. at least
I know a little more about how translations are done and how I can
customise/override elements.
thank you very much
best regards
Oliver