* CookieRevised looks at all the posts
This is the same old story as with Custom emoticons and Display pictures...
MSN Messenger stores everything in it's useuall cache folders...
see:
CookieRevised's reply to re-name display pics?
The files themselfs are renamed, just like CE's and DP's. But simply copying them to back them up isn't enough (just as with CE's and DP's). In every directory there is also a cache file. This file holds the hashes, names, locations, whatever for your CE's, DP's, winks, muggins, etc. And this file is encrypted and encoded.
This means you can not simply copy everything and paste it into someone elses directory and expect it to work. If you want to add them again, you must do it one by one (and first rename them to the proper file extension again) via MSN Messenger itself...
There are "backup" programs for CE's and DP's (see
http://www.sherv.net/), but they do also exactly that, adding all the stuff back via MSN Messenger. I'm sure such backup programs will be made also for winks and stuff, just be patient and keep an eye on sites like mess.be, msnfanatic.com, sherv.net, etc...
PS: and as for those directories where everything is stored, if you search the forums you'll find tons of posts already mentioning it...