Full text search - How to build a filtering dictionary

Hi all,
I need to build a synonym dictionary that performs a normalization of
tokens just like a filtering dictionary does. I've searched for a
filtering dictionary template but I've found it. Where Can I find it?
Or, if there isn't such a template, How can I build a simple filter
dictionary that simply maps a term with another (in a synonym dict-like
way)?

Thanks in advance,
Antonio