I did find it and search around this web site and you will find it too..just type in keep the home-fires burning john mccormack and it is one of the first..

but here is a recording of Christmas sounds in the German trenches in WWI....someone probably was playing a record...

http://www.firstworldwar.com/audio/germanxmas.htm

this is an amazing site...lots of old WWI songs..

mg