S_RFC can´t be adjusted in PFCG

Hi experts,

I have a question regarding the authorization object S_RFC. I have a role which should extend this authorization object. The object can´t be maintained via the role in the Permissions tab in PFCG. How can it be adjusted? But I do NOT want to add the object manually in the role. Do I need to adjust the object in SU24 transaction to the SUIM? Is there a way to adjust the object through the tab menu, such as for object S_SERVICE where authorization proposal must be selected?

thanks!

Ilona