When implementing a Dynamic Process, there currently are three options to implement a case activity: Human Task, Service (or Integration), and Process. At least up to version 18.104.22.168.0 there is limitation when defining the interface in case of a Process Activity making that you cannot use a Business Type which is based on an XSD element, which on its turn in based on a complexType. The below describes the problem you will run into, and a suggestion of how to work-around this.
When developing XSD's for web services you may have developed the practice of defining a complexType with an element based on that complexType, for example as in the below XSD. Reason could be that you developed with the (on-premise) SOA or BPM Suite and found this to give the best flexibility, especially when integrating with Oracle Business Rules. Read the complete article here.
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