node.create xmlrpc

Im looking for help on how to add taxonomies and files to nodes using Java and XMLRPC:

• add taxonomy terms to a node (using term reference fields)
  this is what i got: {field_area={und={0={tid=38}}}...} and its not adding the term to the created node

• add files to a node

• edit/update existing nodes

i cant get anything to work and there's little documentation about how to use the API (which parameters requested etc)

anyone help?