Hi Faisal,
I´ve tried that as well. This is also not possible.
The relation is correct.
The following coding is possible:
LR_ENTITY ?= lr_entity->get_related_entities_by_bpath('BTOrderHeader/*$')->GET_FIRST( ).
LR_ENTITY ?= LR_ENTITY->get_related_entity( IV_RELATION_NAME = '/XYZ/EXT_BOL_RELAT000001').
Thanks, Janine