To get the values of a metadata, the following dom search

var nodes = Ext.dom.Query.select(metadataNode.tagName, metadataNode.parentNode);

should be replace by

var nodes = Ext.dom.Query.select('>' + metadataNode.tagName, metadataNode.parentNode);

If not, if a sub-metadata (in composite, repeater) have the same name, the value of this sub-metadata will be retrieved here.