[plt-scheme] Problem with sxml.plt

Hi,

I've started to play around with the SXML-package from Planet, and right 
away I ran into problems. I'd like to extract all the text from an SXML 
document using the procedure sxml:text.

Here is the code

(require (planet lizorkin/sxml:2:1/sxml))

(define doc
   '(*TOP (html (head (title "My Title"))
                (body (p "My Text")))))

(sxml:text doc)

This returns the empty string "" while according to the documentation I 
would expect something like "My Title My Text". What am I missing?

Regards,
Ralf Seliger