It wont work because it is a seperate app thats shown and not really a local view.
Apple uses the concept of Remote VCs that appear to be in your app but are infact own 'apps':
http://oleb.net/blog/2012/10/remote-view-controllers-in-ios-6/
Question
The MFMailComposeViewController translucency property does not work.
MFMailComposeViewController *mailView = [[MFMailComposeViewController alloc] init];
mailView.navigationBar.translucent = NO;
[self presentModalViewController:mailView animated:YES];
La solution
It wont work because it is a seperate app thats shown and not really a local view.
Apple uses the concept of Remote VCs that appear to be in your app but are infact own 'apps':
http://oleb.net/blog/2012/10/remote-view-controllers-in-ios-6/