Adding multiple objects in an entity that has an association

I have trouble adding multiple objects.  I got a planning. This Planning has an association with “Wagen” (Cars in dutch).    The goal that I have, is to automatically fill my “Planning” with “Wagens” that have a registration date of 2 months and newer every time the user sees the data grid. To achieve this goal, i thought of adding multiple “Wagen” objects into the Planning entity by committing a list. But when I execute the microflow shown underneath on the Planning_NewEdit page, it doesn't seem to work (The debugger shows all the wagens i have in my list, so that does work). I think i'm missing something that is needed to commit this list. Can someone help me out?  
1 answers

Why not create a datasource microflow for the retrieval of those cars? So in the page create a grid or listview containing the Wagen objects and as datasource use a microflow that retrieves all the Wagen from the database with the correct registration date.

And on the topic why your microflow does not work is because you do not attach the TestWagenList on the planning object you are showing. You would need to iterate over your list and set the (seperate?) reference to the planning object.