[plt-scheme] namespace-variable-value missing?

Hi all,

(module test mzscheme

  (require (lib "texpict.ss" "texpict"))

  (namespace-variable-value 'ht-append))

>From docs on namespace-variable-value (version 301.12):
If use-mapping? is true (the default), and if symbol maps to a
top-level variable or an imported variable (see section 8.1), then the
result is the same as evaluating symbol as an expression.

I would expect ht-append to be an imported variable but still, this
doesn't work.

Is it my problem? If it is, is there a way to get the procedure binded
to ht-append?

Cheers,
--
Paulo Jorge Matos - pocm at sat inesc-id pt
Web: http://sat.inesc-id.pt/~pocm
Computer and Software Engineering
INESC-ID - SAT Group