Hello ,
GET_SELECTED_ENTITY_COL is to get the bol entity of the selected entries in inbox result list.
While ON_SEL_FORWARD_TO is actually to change the responsible partner to the specific BP.
If in method CL_CRM_AUI_RESULTVIEW_CONTR->EH_ONFORWARD, you go to the statements:
WHEN OTHERS.
lv_selected_bp = cl_crm_aui_service=>get_forwardto_bp( iv_value = lv_selected_option ).
on_sel_forward_to( lv_selected_bp ).
I would like to suggest you to review the codes in method CL_CRM_AUI_ONEORDER->FORWARD. In this method, the lr_bol_entity is actually the entity for BTOrder->BTAdminH. It should be easy to get this entity from your transactions.
Best Regards, Corrine