not sure if you got it answered but here the best way to tell ya.
when your viewing a journal and want to +rep someone you look in the bottom left of their post. when you see your name and avatar in a post look directly below that and there will be 3 little icons. one will be green if that person is online or it will be translucent if their offline, there will be a cloud looking icon(i have no clue what it is really) but when you click the white cloud thing a pop up will come up, its a comment bar and it has you say why your +repping (optional) the person. then there will be another icon but i cant remember what it is right now lol. hope that helped bud