Change displayed view in a UIPopoverView

Change displayed view in a UIPopoverView

So I'm presenting a UIPopoverView like so:
if (self.BStatePopoverViewController == nil) {
RedStatePopoverViewController *settings =
[[RedStatePopoverViewController alloc]
initWithNibName:@"RedState"
bundle:[NSBundle mainBundle]];
UIPopoverController *popover =
[[UIPopoverController alloc] initWithContentViewController:settings];
popover.delegate = self;
self.BStatePopoverViewController = popover;
}
[BStatePopoverViewController setPopoverContentSize:CGSizeMake(320, 445)];
[self.BStatePopoverViewController presentPopoverFromRect:[sender
bounds] inView:sender
permittedArrowDirections:UIPopoverArrowDirectionAny animated:YES];
Once the view is loaded in the popover, I have a button which I'd like to
use to present a new UIViewController within the popover. I tried just
presenting it as a modal view but this changes the parent view as opposed
to the one in the popover:
PopupDischargeViewController * dischargeview =
[[PopupDischargeViewController alloc]
initWithNibName:@"PopupDischargeViewController" bundle:nil];
[self presentModalViewController:dischargeview animated:NO];
Any help as to how I do this would be much appreciated.
Thanks!