It is currently not possible to create new properties using QS. For wikidata.org, this is not an issue, as property creation is limited to admins and follows formal rules. However with the integration of QS in the wikibase docker image, there is now an increasing amount of wikibase repositories where automated property creation with QS is a useful approach.

For a more detailed description see https://bitbucket.org/magnusmanske/wikidata-todo/issues/113/

(I duplicated this issue here, so I can upload the patch directly to through Gerrit, so it can be easily merged)

Update: solved with https://github.com/magnusmanske/quickstatements/pull/19