Hello,
There has been a while since you posted this thread, hope my current reply could still help a bit.
I am not a business agreement expert, thus not so sure whether business agreement might have any comments regarding this.
But from web ui framework point of view, to have such direct URL working. We have to firstly have a mapping class in table CRMS_UI_OBJ_MAP, it can be seen there is one entry:
BuAg CL_CRM_IC_OBJ_MAPPING_BUAG
but in this mapping class, method IF_CRM_UI_OBJ_MAPPER~GET_ENTITY_FROM_UI_OBJECT has no logic implemented. I guess that is why.
If you check the BP_ACCOUNT scenario, the mapping class is
CL_CRM_BUPA_UIU_OBJ_MAPPER
IF_CRM_UI_OBJ_MAPPER~GET_ENTITY_FROM_UI_OBJECT
in this method there is coding to get the actual bp using the parameter provided in the url.
Thus if you need this function without further wait, you may think of inherit CL_CRM_IC_OBJ_MAPPING_BUAG and implement the mentioned method with logic. Then add one mapping entry in table CRMC_UI_OBJ_MAP pointing to your Z class.
Hongyan