QItemDelegate: and QTreeView

If you want to set a delegate for a particular node in a QTreeView there seems to be no way to achieve this.

itemDelegateForRow doesn't help since it will match for all levels of the hierarchy

E.g.

setItemDelegateForRow(1, new Delegate(this));

A
a1
a2 = > This is the one I want the delegate for.
a3
a4
B => This one will also get the same delegate
C
c1
c2 => This one will also get the same delegate
D

The best thing would be:

virtual QItemDelegate *itemDelegate(const QModelIndex &index) const

but maybe something else (that is binary compatible) can be thought out.