Reusing reusable classes

I am having a real problem with understanding something in flash - it doesn’t work in the way I expect so I figure I have really misunderstood something.

What I want:
I am creating a bunch of .swf files and in each one I want multiple instances of an object that when you put the mouse over it the object will play its animation a bit and pop up a tool tip. Each object can look different (i.e. be a different bitmap) and animate differently (shake, pop, rotate etc).

What I did:
I have tried to create a class (myMouseItem) that creates the necessary listeners to handle the animation and pop up the tool tip.

I create a library item and attach it to the myMouseItem class. I can then put one instance of this inside my .fla and it works. (I still seem to have to put a myMouseItemInstance.stop() in the actionscript for the scene to get it to stop animating for ever but I can probably live with that)

What I can’t figure out:
How do I repeat this with multiple objects all with different bitmaps but reusing the underlying class? When I try to add another instance of my library class and edit the bmp it changes all instances. When I try to create another library item with the same underlying base class I get an error saying that I have to choose a unique identifier, so I don’t seem to be able to reuse my .as file.

I would have thought this kind of thing is something people do all the time so surely the answer is simple? I just can’t figure it out :frowning: