Configure Emacs to autocomplete the tags

Hi,

    

    I just
        installed Debian Jessie and installed
      the packages to use
      DocBook with Emacs:

    

    

      
bash# 
          apt-get install  docbook-xsl
              xsltproc

      

      

        
bash# 
            apt-get install  emacs 
        

      

    

    

      What I need to do to
        for  Emacs
      to autocomplete the tags.

      

      This feature worked
      in Squeeze.

      

      Any tip?

      

      Thanks,

      Markos