Is it possible to create the following situation in Mendix: Create a microflow with two input parameters (Objects). Create an 'Call webservice' activity. The first parameter should be the same object as the object that is created by the 'Call webservice' activity. This is needed because there are fields necessary in the request but will not be returned in the response. The 'Call webservice' activity should therefore add the additional information to the first parameter object. Create a change activity for the object just created in the 'Call webservice' activity and set the reference to the second input parameter.
Marco de Kievit
Yes it is possible. You should pass the input parameter to the webservice call and its mapping. Then, in the mapping, use a microflow to create the new object and set the reference.
As far as i can see, the answer still holds, in the mapping lookup the object using a microflow ('custom' option), and pass that microflow the first argument and return it immediately. I used that successfully in the past. In the call activity, under 'Map to entities' a parameter dropdown should appear in which you can select the first input parameter.
How about setting a reference between the two input parameters (possibly with a third object to temporarily hold this info) so that you have access to both in the mappings?