The accepted answer does not really answer the question, "is there a way NOT to have the popover dismissed when pressing outside it?", imo. It does give a possible view but could require hackish access to all parent views and determining what views are on the screen etc. The question could be rephrased as, "how do I make a popover view modal?"
You would do this like so, with a done button to close the popover:
UIViewController* vc = [[[UIViewController alloc] init] autorelease];
UIBarButtonItem* doneButton = [[[UIBarButtonItem alloc] initWithTitle:@"Done"] style:UIBarButtonItemStyleDone target:self action:@selector(processDoneAction)] autorelease];
[vc.navigationItem setLeftBarButtonItem:doneButton];
vc.modalInPopover = YES;
//If you want full screen:
vc.modalPresentationStyle = UIModalPresentationFullScreen;
vc.wantsFullScreenLayout = YES;
UINavigationController* navC = [[[UINavigationController alloc] initWithRootViewController:vc] autorelease];
UIView* view = create your view
vc.view = view;
UIPopoverController* pc = [[[UIPopoverController alloc] initWithContentViewController:navC] autorelease];
pc.delegate = self;
self.popoverController = pc;
Then you'll in your processDoneAction method you will need to dismiss the popover. Other considerations would be dismissing and redisplaying on device orientation changes, but I will leave that to another exercise as that has been answered previously on stackoverflow.