HTML backend - element undefined

["Ubik Sven" <UBIK@xxxxxxxxxxxx>]

I tried to use formatting-instruction flow object class formerly
documented in http://www.jclark.com/jade as implemented in Jade
to support the HTML backend. I tried an example given in the cited
document:

(declare-flow-object-class formatting-instruction
  "UNREGISTERED::James Clark//Flow Object Class::formatting-instruction")

(element q
  (sosofo-append
    (make formatting-instruction
      data: "<pre>")
    (process-children)
    (make formatting-instruction
      data: "</pre>")))

But Jade responded:

jade:pokus.dsl:17:15:E: element "PRE" undefined

How can I define the "PRE" element? Is the HTML backend still supported?
I found that it is now not mentioned in http://www.jclark.com page.
I use Jade 0.5 in Solaris 2.3.

Sven Ubik

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Sven Ubik                      Faculty of Mechanical Engineering
                               Czech Technical University
E-mail:  ubik@xxxxxxxxxxxx     Technicka 4, Prague 6, 166 07
         ubik@xxxxxxx          Czech Republic
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