I finally cracked the code! You use a combination of XBMC functions that are already assigned, and then create new ones that are not being used by you. You do indeed need a remote.xml file for anything custom. I now have Aspect Ratio working. I used green & blue as keys since I don't have them on my remote. Here they are:
Lircmap.xmlKEY_PAUSE KEY_INFO KEY_NUMERIC_STAR KEY_PVR KEY_TV KEY_ANGLE KEY_EPGremote.xmlContextMenu AspectRatio
Glad you managed to get this sorted, sorry, I have been away for a few days. Welcome to the mysterious world of LIRC.
Can you please mark your last post as answered, it may help others find the your solution quicker.
Thanks