Since I was updating my own UI for SoM, I see you've got a nice list in the beginning of this topic. Some things are still missing, for example which <Mapping ArtAssetID ..> is used for Skirmish Join etc.
I've found a nice UI with all links for SoM elsewhere on this forum. Probably you have found it also, if not:
You can also find some of those mappings implemented in my UI, so you can use that Skindefinition.xml as well.
Thanks for making/updating this topic Daimon