DocBook to PDF and page references

Hello,

is it possible to generate an index with the standard DocBook stylesheets and 
PassiveTeX? Is it generally possible to generate indexes when going via FO?

I suppose that FO is not concrete enough to already make the breakdown into 
pages. So it seems that on the FO level one doesn't know on which pages the 
terms in the index will reside, and therefore the stylesheets won't be able 
to insert the correct page numbers in the index.

Am I wrong here?

Wolfgang