[FLOW3-general] query->isEmpty returns no NULL properties

[Thomas Mammitzsch]

Hi list,

i try to get objects which have a property which might be NULL in some 
cases. Because the is no isNull() constraint method i tried isEmpty() 
which should work ("It matches if the multivalued property contains no 
values or is NULL."). But it doesn't.

         $query = $this->createQuery();
         $query->matching(
             $query->isEmpty('someproperty')
         );
	
	return $query->execute()

any ideas or hints?