[NTG-context] Sorting references

[Jean Magnan de Bornier]

Hi all,
Using the bib module, I want my references to be sorted alphabetically; if
I understood correctly the doc:

\setuppublications[alternative=apa-fr,sorttype=bbl,criterium=cite]

Then the alphabetical order is taken from the bibtex *keys*, and it
doesn't always follows true alphabetical order... :-(

And it seems that with bbl the whole bbl content is necessarily written in
references.

How can I do to have only cited material included in references?

TIA,
-- 
Jean