Okay, here you are:
Some units don't have buttons like these (horse archer, longbowman, tank), so they're not included.
To use a weapon, simply turn on the visibility for the layer you want to use (in the same way as the backgrounds).
If you want to make a flag, turn off all layers except 'Border', 'Flag Layer Top', 'Flag Layer Bottom' and 'Paste Graphic Here'.
Also, if you want a skyline with another background, turn on 'Unit Air Bgr TOP', which allows you to have a desert or grass skyline if you wish.
This comes only in GIMP format. If someone (like Snipper) want it converted to PDN, I'll have a go.
See file at the end of the post.
If anyone would like any more info, post here.
Some examples of this in action can be found in Chuggi's Flavour Workers thread, where I am about to post buttons for them.