Set NCM Credentials

Hello all -

I've managed to successfully create nodes using v3, and add that node to NCM with v2.  One thing I am not seeing though is  how to set the credentials for NCM?

I used

XmlDocument xdoc = new System.Xml.XmlDocument();

XmlElement[] elem = new System.Xml.XmlElement[1];

XmlElement xel = xdoc.CreateElement("coreNodeId");

this._NodeID.ToString();

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

Is there part of the XML that would set the credentials?