Forward reference in Sweave

Dear Rweavers,

When generating reports with Sweave, I would like to quote some results in
the abstract (Something like "The treatment effect is 10 mbar, see page
100).

Currently, I used verbatimwrite and friends to write to multiple files to be
included,  but I wonder is there is a more elegant method for such
accumulated forward references in one file similar to toc creation.

Sorry if this is a latex-question, but it looks like most latexer are happy
with toc and index forward references. Maybe I used the wrong keywords for a
search.

Dieter