I use Voice Attack for several commands, including Docking Request,
here is a link to a voice pack that has hundreds of commands and responses. not free but still not expensive.
http://www.elitedangerousvoicepack.com/
Here is the actual Voice attack key sequence, you could use the keypresses on a Logitech keyboard or similar.
Play sound, '{VA_SOUNDS}\hcspack\UPDATE 1.4 OCTOBER 2014\request for docking sent.mp3'
Press 1 key and hold for 0.1 seconds and release
Pause 0.2 seconds
Press E key and hold for 0.1 seconds and release
Pause 0.2 seconds
Press E key and hold for 0.1 seconds and release
Pause 0.2 seconds
Press Space key and hold for 0.1 seconds and release
Pause 0.2 seconds
Press S key and hold for 0.1 seconds and release
Pause 0.3 seconds
Press Space key and hold for 0.1 seconds and release
Pause 0.2 seconds
Press 1 key and hold for 0.1 seconds and release
Pause 0.2 seconds
Press [ { key and hold for 0.1 seconds and release
Pause 0.2 seconds
Press 2 key and hold for 0.1 seconds and release
Pause 0.2 seconds
Press 2 key and hold for 0.1 seconds and release