I have an iPhone 4, a 3rd generation iPad, and a Mac. I have Dropbox on each device. I cannot figure out how to save an email message, OR an attachment, OR a photo, or a document to Dropbox on my phone or iPad?! The "share" button brings up various options (Mail, Twitter, FB, Assign to Contact, Save Imagine, Print, Copy, etc.) but never Dropbox. Am I missing something obvious? THANK YOU very much!