OK you don't seem to understand what I'm asking so i'm making a guess your using a .xib file to add you UI stuff?
if so you need to use this:
[[DetailViewController alloc] initWithNibName:@"DetailViewController" bundle:nil]
change NIBName
to whatever yours is.
EDIT
To do this with a storyboard you need to give the viewController a storyboardID and init it manually. Follow the steps outlined here: http://averagepro.com/2013/02/07/instantiate-storyboard-viewcontrollers-manually/
its roughly:
self.detailViewController = [[self.storyboard storyboardWithName:@"storyboard"bundle:nil] instantiateViewControllerWithIdentifier:@"DetailViewController"];