[Mediawiki-api] Parameter apprefix for allpages request

[Nicolas Vervelle]

Hi,

When looking at the documentation you get when callling the API, the 
apprefix parameter is documented as "Search for all page titles that 
begin with this value" but I don't get any result when I try to use it.

For example, the following request returns zero pages :
http://en.wikipedia.org/w/api.php?action=query&list=allpages&apprefix=Bal&apfrom=bal

How do you use apprefix ?

Nico