iOS 6 Getting Directions in new Apple Map on Foot or Walking

Question

I'm unable get the Walking directions using Apple Map app, But if use MKLaunchOptionsDirectionsModeDriving rather than MKLaunchOptionsDirectionsModeWalking the code works, can someone please help a bit getting on Walking directions?

I have following code for getting directions, which is working for Driving case...

MKPlacemark* place = [[MKPlacemark alloc] initWithCoordinate:_targetLocation addressDictionary:nil];
MKMapItem* destination = [[MKMapItem alloc] initWithPlacemark:place];
destination.name = [lastParkingInfo streetAddress];
NSArray* items = [[NSArray alloc] initWithObjects: destination, nil];
NSDictionary* options = [[NSDictionary alloc] initWithObjectsAndKeys:MKLaunchOptionsDirectionsModeDriving,MKLaunchOptionsDirectionsModeKey, nil];
[MKMapItem openMapsWithItems:items launchOptions:options];