Uploads the text document to the server. The object
record of the document may not be modified while the document
is edited. This function will only works for pure text
documents. It will not open a special data connection and
therefore blocks the control connection during the
transfer.
See also hw_pipedocument(),
hw_free_document(),
hw_document_bodytag(),
hw_document_size(),
hw_output_document(),
hw_gettext().