Hi Jirka,
I ran into this same problem when creating the beta epub3 stylesheets. I had to add
some templates for isbn, issn, and biblioid for epub metadata, so I needed to include
an updated titlepage.templates.xsl in the beta distribution. For the beta, I admit I
just edited it by hand after generating it so it would have that default namespace and
work in the beta. I presume you created a custom version from template/titlepage.xsl,
and that is where that namespace gets lost.
I think perhaps we need separate template/titlepage.xsl files for the different
namespaced outputs. I haven't looked into it yet, but that would probably be easier
than trying to do it with one stylesheet and different namespaces. I'm not sure how
to do it, though.
Bob Stayton
Sagehill Enterprises
bobs@sagehill.net