Can't open email files using file-opener2 on iOS

[nareshbhatia]

I found an app on iOS that can open email files (.eml and .msg): Msg Viewer Pro. Tried it with some sample emails in my Dropbox. The Dropbox app opens up a tray at the bottom and allows me to choose an app to open the file. Msg Viewer Pro shows up in this tray and tapping on it opens the email.

However, I can't get the same functionality to work with file-opener2. I tried it two ways, by sending a MIME type of "message/rfc822" and a MIME type of blank (""). In both cases the code in FileOpener2.m returns a UTI of com.apple.mail.email, which does not open Msg Viewer Pro. I get Error status 9 (Could not handle UTI).

Talking to the author of the app, he has registered it to open .eml and .msg files (not a MIME type as far as I can tell). Also he recommends using the tray interface to open files:

[UIDocumentInteractionController interactionControllerWithURL:URL];
self.interactionController.delegate =  self;
[self.interactionController presentOptionsMenuFromBarButtonItem:sender animated:YES];

This is the best information I have. I am not an iOS developer, so don't know where to go from here. Any suggestions? Is it possible to add the tray interface as indicated above for the Mac platform?