[Flow] How to define targetEntity in abstractClass

[Alexander Wende]

There is an example from bastian how to implement doctrine extensions: https://gist.github.com/bwaidelich/9617211

Unfortunately it does not work on my system. 

Trying to enable the filter manually results in "Filter 'soft-deleteable' does not exist." Exception.
        $filterCollection = new \Doctrine\ORM\Query\FilterCollection($this->entityManager);
        $filterCollection->enable('soft-deleteable');


Package is installed via composer.  Flow version is 2.2 . No other error appear.

 I am grateful for all hints - maybe some one has time to check if it works on another system.