I am developing an web app that lets you see your Facebook wall posts and replay/comment on those as a Facebook page not user. The problem i am running into is that i cant find the proper token or validation method to do so. The functionality i'm looking for is that certain amount of users log into my app and are able to post to Facebook Page wall as that page. I was trying to do a long term access token thing but it seems to expire too early. What would be a correct way to do this kind of task?