Let's follow up this discussion at the Neptune Community
(this forum will be kept in read-only mode)
Is it possible to prepare data for the RoadMap object in the back end?
Should I use some Internal table with "special" structure?
Where and how the model should be mapped in Designer?
You may try to put your roadMap/roadMapSteps elements into an HBox element which is bound with a structure defined as global variable in the backend.
In this way, the roadMap/roadMapSteps properties will be bindable as HBox is the parent node.