Hi, Roei Sagi!
To remove the 100 limitation, you must set the filter class to the relation BuilIObjRel.
Maintain table CRMC_MODEL_BUIL, search entry by RELATION_NAME = 'BuilIObjRel' and set FILTER_CLASS = 'CL_BUPA_IL_ATRS_FILTER'.
Then use the same code to get IObj collection:
DATA: lr_filter TYPE REF TO cl_crm_bol_relation_filter,
lv_collection TYPE REF TO if_bol_bo_col.
lr_filter = cl_crm_bol_relation_filter=>get_instance( iv_relation_name = 'BuilIObjRel' ).
lr_filter->set_property( iv_attr_name = 'MAX_HITS' "#EC NOTEXT
iv_value = '9999' ).
lv_collection = lr_entity->get_related_entities_by_filter(
iv_filter = lr_filter
).