XML-RPC to node.save

Hi,

I'm trying to save a node with a date CCK field using XML-RPC. I'm using C Sharp and XML-RPC.NET. The structure I follow is this:

XmlRpcStruct hval = new XmlRpcStruct();
hval.Add("value", "2010-01-21T20:00:00"); //format ISO-8601.

XmlRpcStruct hdate = new XmlRpcStruct();
hdate.Add("date", hval);

Object[] odate = { hdate };// new XmlRpcStruct();
node["field_date"] = odate;

drupal.NodeSave(
Session_id,
node);

The answer I receive from the server is always the same:

CookComputing.XmlRpc.XmlRpcIllFormedXmlException was unhandled
Message="Response from server does not contain valid XML."
Source="CookComputing.XmlRpcV2"

Any clue?. Maybe the struct I'm using is not correct?

Thanks!