Put it on with tie wire.  Few wraps around the barb wire next to the post then wrap around the post and back to the barb wire on the other side of the post and few wraps, cut the tie wire and your done.   22.6 seconds and you don't have to worry about whether you broke the barrier or not. 

My posts lying around right now are only about 4 to 5 foot long.  Shorties so to speak for bracing.  Not sure you could get:

RICH M***** aka DR. LOVE

on that short of a post.