Any device key can be programmed with code from any device type, but you have to change it that device like so; say you want to use AUX device key:

1. aux
2. press and hold SET
3. press SELECT
4. using the DOWN CURSOR key, scroll until the device name changes to LDP
5. press SELECT, since code 0059 is already in the display
6. exit

if code 0059 wasn't already in the display, you enter it and then press select in step 5.