[Zope] Pre-indexing filter and accented letters

[Yuri]

I would like to index a text property of an object in the ZCatalog. The 
text is in French language, but I have a problem: I have to find results 
for the related non accented letters!

 I mean, If I do a search for  "actualite", the index should return also 
the object which text contains "actualitè".

 I cannot convert the index to textindexNG, now it is TextIndex (at 
least, I can covert it to ZCTextIndex).

 An idea could be, for example, to convert the text before it get indexed...

 Where should I look in the code? Can it be possible? Any other 
suggestion? :)

 TIA!