xmlrpc specifications for performancing

I'd like to add xmlrpc to a project so I can post internally using performancing.

Is there a Performancing xml-rpc spec which shows how to program server side stuff using xml-rpc - or is there a higher level specification which performancing adheres to?

I'm no whiz - but i guess it will include stuff like

performancing.getCategories( )
Returns an array of structs of available categories (member "title"), each with its associated category ID (member "id").

performancing.getLogin(id,password)
Returns true if login and id are correct - false otherwise.

etc etc .

any hints and tips? Is there such a document? What can developers recommend I read if I want to add rpc-xml to a project?

tnx in advance