I have some news.
1) Using the Create Entry and mapping the correlation ID you get an entry in stub form. but the entry is not fully filled and contains only request id.
2) the Service Request doesn't go immediately to closed if you use the Receive task element. This one is not required anymore from 19.02 but required for the use case where you use create entry to create ticket.
3) the problem with missing data in stub form is that the ticket status update is not synchronized to stub form. If you want to have this you have two options:
a. you update the workflow in itsm that the update of stub form will not search ticket number but requestid
b. or you will extend your workflow in DWP Catalog and update the entry in stub form from there to have all data inside and then you get the ticket status update automatically
Still one disadvantage - in DWPC Service Requests list the service request has empty activity list. so the ticket created like this is not really connected/related to the DWPC Request.