[Zope] Catalog problems

OK, here's the situation. I want to build a search engine that applies to a particular folder and all its sub-folders. I want this search engine to be a FULL TEXT one, meaning it will need to search through the body text of documents. I have been unable to figure out how to set this up with catalogs. Do any of you have some pointers to help me out? Specifically, I can't figure out how to limit it to one particular folder, and how to tell it to do a full text index. -- John