The doc says it's not using a PK on the PK side but a UC, which means the relationship isn't recognized. As the relationship isn't recognized you can't map a reference/collection (field) on the relationship, so you can't use a prefetch path for this relationship (edge).
I wonder why the fk in the DB points to a UC. The whole AccountsPayableDetail table is odd to me as well.
We would like to bring AccountsPayable entity with its related AccountPayableDetails colletion
This doesn't make sense to me as well: the diagram doesn't show any direct relationship between the two, even through supertypes. AccountPayableDetail is related to AccountTransactionDetail, but that isn't directly related to AccountsPayable.