UPDATE:
I also tried implementing UITextViewDelegate delegate and then doing in my controller:
- (BOOL)textViewShouldEndEditing:(UITextView *)textVie
In Interface Builder on the properties of the textView you can set the return button type to Done.
Then you need to check for when the Return button is pressed using
- (BOOL)textView:(UITextView *)textView shouldChangeTextInRange:(NSRange)range replacementText:(NSString *)text
Check if the text == "/n" then dismiss the keyboard by resigning first responder on your textView.