1 Eldritch Scroll + 1 Gift of Ice + 100 Mystic Coins + 250 Ancient Short-Bow Staves
Credit goes to Glaciair
http://www.reddit.com/r/Guildwars2/comments/11s7yd/world_first_wintersbark/
A few people think if you can make the longbow version by switching the Short-bow staves with longbow ones.
Enjoy!
Battlelord Taeres