Barney,
How are you doing the mapping? Through a MAP and using the drag and drop or through variable substitution? Also, how are you converting the XML into a record? Using a recordName to format it? I have not seen any issue with getting or setting attributes before.
I have noted a related bug in WM 46 TN implementation. When performing either pub.web.documentToRecord or wm.ip.util.documentToRecord the @XMLSNS attribute is being lost. I have spoken with WM support regarding this issue and I was told that xml namespace declarations are not mapped at the record level, but are at the node level.
To get around the problem we are having, which is a missing namespace declaration, we added a map set in after the documentToRecord step and hardcode the @xmlns attribute.
HTH