How can I 'show black screen' on the remote computer when using an iphone

When I access my computer using a laptop or PC I have the 'actions' menu at the top and I can access the option to 'show black screen' on the remote computer. When I access the remote computer from my iphone I do not get the menu options above. The only menus or options I get do not seem to have the option to 'show black screen'. How Can I do it?