Bukkit

What is the issue?
New Attribute System

When trying to add a new attribute to an object such as generic.movementSpeed I manage to do everything correctly (Following http://www.minecraftwiki.net/wiki/Player.dat_Format) and save the object, but when I try to look at the item it seems to reset. Here's what I did

(Diamond boots in slot 0)

/nbt
player me
cd inventory
cd 0
newcompound tag
cd tag
newlist AttributeModifiers
cd AttributeModifiers
newcompound
cd 0
newstring Name (insert whatever)
newstring AttributeName generic.movementSpeed
newdouble Amount 2
newint Operation 0
newlong UUIDMost (random numbers)
newlong UUIDLeast (random numbers)
save
exit

Now it works if I don't change slots via scrollwheel or open my inventory, but If I do the item loses any new attributes. Help?

That's odd, I'm thinking it might be a problem with the UUIDs. The mechanism of the plugin works the same for everything so it's nothing I can fix. If the minecraft code finds tags that don't seem right, it'll just erase them. It might just be something that's not ironed out yet on the client side.