How to use Custom property drawers in a ScriptableObject inspector?

My custom property drawers are being applied to fields of MonoBehaviours when drawing a gameobject inspector. But an inspector of a ScriptableObject asset ignores custom property drawers, it shows the default field drawers instead.

Is there a way around this?

The ScriptableObject class name has to match the name of the file it lives in.

Figured it out with great help by the forum.