Hello Marek,
this is a bit complicated. The easy way would be this:
Create a task called "Clip reciept" or something like that, assign that to the department and give the task only one decision, called "reciepts clipped". Teach the users how they clip documents (right click in list -> clip, or via toolbar) and tell them to only confirm this task if they have clipped something to the document.
However, this way you have no way to validate if they actually clipped something or just confirmed without doing so. You can not stop users from confirming the task without clipping something.
If that is what you need, you probably have to take a look at the REST API over at
developer.docuware.com , that way you can clip and validate it as well. As far as I know, this is not possible with just the workflow manager.
Hope this helps.
Greetings from Germany,
Simon H. Hellmann
DocuWare System Consultant