how do i play splitscreen on star wars battlefront without having to be a guest.

i saved up for a new skin for a guy on my account on our xbox, and i wanted to play splitscreen with my brother. so he was the primary user and we played splitscreen, but my new person wasnt there because i was a guest. is there any way to play splitscreen with two separate accounts, not one single account and a guest. FYI this is star wars battlefront two im talking about. any solutions on how i can use my skin on splitscreen.