I like set the Facebook permissions scope. As example user_about_me and email. I find this solution in web:
Dictionary<String, Object> facebookPermissions = new Dictionary<string, object>();
facebookPermissions.Add("scope", "email,user_about_me");
OAuthWebSecurity.RegisterFacebookClient(OAuthService.AppId, OAuthService.AppSecret, "facebook", facebookPermissions);
But doesn't work. The Facebook login doesn't show me the needed permission for my Facebook App. And the URL have no defined scope..