More specifically, the node that I need to retrieve an attribute from is
<xsf:xDocumentClass solutionFormatVersion="2.0.0.0" solutionVersion="1.0.0.575" productVersion="12.0.0" requireFullTrust="yes" name="urn:schemas-microsoft-com:office:infopath:FormName:-myXSD-2008-06-30T14-56-08" ...