FYI - Upon inspecting the XML I noticed something other Knimers might struggle with. Colons in the attribute names:
To level the playing field, this has been flagged before and there is a workaround available using indirect XPath declarations like @*[name()='<attribute:name>'] . e.g.:
/rdf:Description/@*[name()='aux:Firmware'] (in courtesy of @armingrudd 
). Read more in this thread:
Enjoy the challenge!
Edit: Here is a sample XPath as this aspect might be rather annoying //*[local-name()='Name' and @xml:lang='en']/text()