DOCBOOK: xref text

The doc says that:

"A straight link generates the cross-reference text: Chapter 2, "The
Second Chapter""

Though in my case, the quoted title is not shown
The following example just says:
See Chapter 1.

Is there a parameter to change? I couldn't find it.

Thanks, Camille.

----------------

[...]
<preface><title>pr嶨ace</title>
<para> 
See <xref linkend="samba">.
</para>
</preface>
<chapter id="samba"><title>SAMBA</title>

<sect1><title>What is samba?</title>
[...]