Manually creating MasterDetailEditor

Ok I take the blue pill, I deprecate Form and try to use FieldGroup with bindMemberFields.
I visually design the form with eclipse plugin but again my domain/model has @oneToMany
So what component do I bind to @oneToMany?
Can I drag&drop or manually create a JPAContainer MasterDetailEditor?
If not is there an equivalent component that I can bind with bindMemberFields?
And if I am creating a new item, how can I avoid null pointer in MasterDetailEditor?