A list of supported product keys can be found in the Lansweeper configuration console under Scanning Options\Product Keys. If you know of additional registry locations that store product keys, you can manually add them to the list.
Rescan your computers afterwards by selecting them in the Lansweeper configuration console under Lansweeper\Scanned Computers and hitting the Full Rescan button. Scanned product keys can be found in the Keys tab of computer webpages and in the built-in report "License: Software licensekey overview".