Add Node to NCM via .NET

Trying to add a node to NCM using the SDK with C# .NET. Have the following code:

System.Xml.XmlDocument xdoc = new System.Xml.XmlDocument();
System.Xml.XmlElement[] elem = new System.Xml.XmlElement[1];
System.Xml.XmlElement xel = xdoc.CreateElement("coreNodeId");
xel.InnerText = nodeID.ToString();
elem[0] = xel;

client.Invoke("Cirrus.Nodes", "AddNodeToNCM", elem);

Following exception results: "Invoke failed, check fault information."

Where can I check this fault info? Seems like this should work from looking around the message board.

Also - Can I set the NCM Global Connection Profile using the SDK in a similar way?