updating ogo users via xmlrpc

Hello,

I am trying to update ogo accounts via xmlrpc ( in php ).  In this file :
http://docs.opengroupware.org/Members/bjoern/xml-rpc-en.pdf on page
33 there is the statement "AccountDocument. Must contain the account 
number."

Where can I find what is the correct field name for this ?

   $rpc_message = array (
                  'what must go here ?'   => new 
XML_RPC_Value($account_id, "string"),
                  'login'   => new XML_RPC_Value($struct->login, "string"),
                  'name'   => new XML_RPC_Value($struct->name, "string"),
                  'password'   => new XML_RPC_Value($struct->password, 
"string"),
                  'firstname'   => new XML_RPC_Value($struct->firstname, 
"string"),
             );

I tried several possibilities, but they all gave this error:

Jun 18 12:36:07 xmlrpcd [3069]: >DirectAction> Fault[2] occured: Missing 
ID in account record

I hope somebody can help or give me a document/site where al documents 
are described with their properties.

thanks in advance,

Matthias Wies
Netland Internet Services B.V.