UIActivityViewController - Email and Twitter sharing

I recently started working with UIActivity to share my app to the world, but I have few problems. First, I didn't find how to set the subject of my email. Is there any way? Second, when I set the body text of my email, there is a extra "enter" (first line of the email is blank and my text starts at the second line). Here's the code:

 NSMutableArray *array = [[NSMutableArray alloc] initWithObjects: @"Test", nil];

    UIActivityViewController *activityViewController = [[UIActivityViewController alloc]
                                   initWithActivityItems:array applicationActivities:nil];

And in the email, it shows that:

"

Test "

Third: is there a way to know which sharing method has been selected? Because I want to include a hashtag in my post when the user shares on twitter, but now it gets integrated in the email also, which obviously doesn't make sense.

Thanks!