These are standart actions for UIMenuController declared http://developer.apple.com/library/ios/#documentation/uikit/reference/UIResponderStandardEditActions_Protocol/UIResponderStandardEditActions.html
How can I perform these methods manually, like from another UIMenuItem or whatever? I can't find the right selector:(
So far non of these don't work, selector not found.
You need to send the action along the responder chain, starting with the "first responder". Try this:
[[UIApplication sharedApplication] sendAction:@selector(cut:) to:nil from:self forEvent:nil];
If you have the UIEvent that triggered the action, you might pass that as the last parameter.
You can read about the responder chain in Event Handling Guide for iOS: Event Delivery: The Responder Chain.