Webビューのボタンは、完了したボタンスタイルの半透明のUIToolbarを使用します。
UISegmentedControl* segmentedControl = [[UISegmentedControl alloc] initWithItems:[NSArray arrayWithObjects:@"Previous", @"Next", nil]];
segmentedControl.segmentedControlStyle = UISegmentedControlStyleBar;
segmentedControl.tintColor = [UIColor blackColor];
segmentedControl.momentary = YES;
UIBarButtonItem* segmentedControlItem = [[UIBarButtonItem alloc] initWithCustomView:segmentedControl];
UIBarButtonItem* item = [[UIBarButtonItem alloc] initWithTitle:@"OK" style:UIBarButtonItemStyleDone target:self action:@selector(done:)];
UIBarButtonItem* flexSpace = [[UIBarButtonItem alloc] initWithBarButtonSystemItem:UIBarButtonSystemItemFlexibleSpace target:nil action:NULL];
UIToolbar* toolbar = [[UIToolbar alloc] initWithFrame:CGRectMake(0.0f, 0.0f, 320.0f, 44.0f)];
toolbar.barStyle = UIBarStyleBlack;
toolbar.translucent = YES;
toolbar.items = [NSArray arrayWithObjects:segmentedControlItem, flexSpace, item, nil];
[self.view addSubview:toolbar];