There are 3 ways how to show stickers:
1) Via SmileyAdd's "Custom smileys" - you need to enable it in FB account options, but it won't work very good.
* it works only for single conversations
* it works only for incomming messages
* it works only occasionally - somehow it just won't show anything, I'm not sure why.
* it works only on newly received messages, it usually won't show historical stickers for history messages (after Miranda restart)
It's because how it is implemented in SmileyAdd. Could be improved in future, but we need someone to do it (in SmileyAdd).
2) Via IEView
* as I'm showing also image URL in sticker message, you don't need some special template to work with stickers, as it usually transform all URLs to image thumbnails
* this won't work in group chats, because ieview is not supported there
3) Via custom smileypack
* you need to prepare own smileypack
* you define [[sticker:123456789]]
as smiley string (with different numeric ids) and attach wanted image (manually download it)
* you will see only stickers defined in your smileypack (but as classic smileys = will work all the time)
* you can also send stickers (by sending the above mentioned string as whole message - without other text)
EDIT: I also just wrote it to wiki - http://wiki.miranda-ng.org/index.php?title=Plugin:Facebook/en#How_to_show_stickers.3F