How to share on a facebook page from iOs App - Objective-c?

Question

When i share a link from my iOs App (with UIActivityViewController) i could share a link only on my Facebook profile or Facebook's group. How can i share on a Page? I have the "Facebook pages manager" app installed on my device, however the app doesn't appear on the list .

NSString *text = @"https://stackoverflow.com/questions/ask";
NSArray *activityItems = @[text];

NSArray * applicationActivities = nil;
NSArray * excludeActivities = @[];//@[UIActivityTypeAssignToContact, UIActivityTypeCopyToPasteboard, UIActivityTypePostToWeibo, UIActivityTypePrint, UIActivityTypeMessage];

UIActivityViewController * activityController = [[UIActivityViewController alloc] initWithActivityItems:activityItems applicationActivities:applicationActivities];
activityController.excludedActivityTypes = excludeActivities;

UIViewController *vc = ...my controller..;

// iOS 8 - Set the Anchor Point for the popover
if ( [activityController respondsToSelector:@selector(popoverPresentationController)] ) {
    activityController.popoverPresentationController.sourceView = vc.view;
}

[vc presentViewController:activityController animated:YES completion:nil];

I also try with Facebook SDK, but the results it's the same, i can't post on a page.

NSURL *nsurl = @"https://stackoverflow.com/questions/ask";

SYContainerViewController *vc = ...my controller..;
FBSDKShareLinkContent *content =[[FBSDKShareLinkContent alloc] init];
content.contentURL = nsurl;
[FBSDKShareDialog showFromViewController:vc withContent:content delegate:nil];

this is what i see: