A little enhancement of Orbiters Remote Control plugin to let the user send keypress events to remote vessels. This doesn't enable full keyboard control of the remote vessel though, only keys that are handled as buffered keys by the remote vessel will work.
To send a key event to the remote vessel, make sure the edit box at the bottom of the dialog window has input focus (Cursor blinking inside of it) and press the key or key combination you want to send.
requires Orbiter 2010
source code included