Thanks for the revised example. Especially the CustomXMLMappings part. Your input has been extremely helpful.

I think I'm still a ways off fully understanding the nuances for MS XML management however I am now at a place where I can replicate reading and writing to a CustomDocumentProperty so can escape the restrctions of 256 character string length limits.

1. I can create a name space
2. I can add add/remove node elements
3. I can add/remove nodes with attributes
4. using an ID attribute I can find any single node
5. I can change the value of elements for a selected node

This will enable me to move a bunch custom document properties used to record information that needs to persist across editing sessions to xml, and more importantly simplify greatly the links to the various checkboxes and buttons in a custom ribbonUI as I can now use the identifiers for persistent values as the Custom UI identifiers and as keys into a dictionary of dictionaries (used to save the property value and the state of the Ribbon control).