Catalog API - REST HTTP POST request parameters?

Hello all

We do not seem to be able to programmatically use this API. The Catalog API (beta) guide ( http://store.yahoo.com/lib/vw/catalog-api-guide.pdf ) does not contain important information on HTTP POST request parameters which should be included in the request:
 
- encoding type ('application/x-www-form-urlencoded', "multipart/form-data", other?)
- request parameter names if applicable
 
Other relevant sources (such as http://developer.yahoo.com/java/howto-reqRestJava.html which lists "appid", "query", "results" HTTP POST request parameters which do not work for us) do not help
 
What encoding type should HTTP POST request have, and what are names of parameters that should be included in the request?
 
Thanks Mikhail A.Golovanov