Many thanks, especially to Jacob Hookom,
his suggestion to use ui:fragment seems to work perfectly:
<webuijsf:head>
<f:facet name="title">
<ui:fragment>Test Xxx -${" "}<ui:insert
name="title">Welcome</ui:insert></ui:fragment>
</f:facet>
Also, someone mentioned replacing ${" "} with   - while it turned
out to be irrevelant to the problem, it's worth mentioning   is a
non-breaking space, , not a "normal" space. Normal space would be
  .
http://www.sightspecific.com/~mosh/WWW_FAQ/nbsp.html
http://en.wikipedia.org/wiki/Non-breaking_space
http://en.wikipedia.org/wiki/Space_character
Greetings, Lilianne E. Blaze
Lilianne E. Blaze wrote:
> I'm trying to get
>
> <webuijsf:head>
> <f:facet name="title">
> Test Xxx -${" "}<ui:insert name="title">Welcome</ui:insert>
> </f:facet>
>
> To work.
(...)