title: UIActivityController behaviour different on device and simulator
body: <p>I add an activityViewController to my app like below, passing in an image</p>
  
  <pre><code>UIActivityViewController *avc = [[UIActivityViewController alloc]initWithActivityItems:[NSArray arrayWithObjects:img,nil] applicationActivities:[NSArray arrayWithObjects:nil]];
          [self presentModalViewController:avc animated:YES];
          [avc release];
  </code></pre>
  
  <p><strong>On the simulator (twitter, facebook and weibo accounts all not configured):</strong></p>
  
  <p>options mail, twitter, facebook, weibo, assign to contact, save to camera roll, print, and copy appear by default.</p>
  
  <p><strong>but on device:</strong></p>
  
  <p>in my app: twitter, facebook and weibo only show if the accounts are configured.</p>
  
  <p>in safari: twitter, facebook and weibo options are available irregardless of whether the accounts are configured.</p>
  
  <p>I am expecting the same behaviour in my app as safari. am I missing a particular step?</p>