XCode 4.2: Where has "Value Transformer Name" gone for Core Data attribute type 'Transformable'?

I'm creating an NSValueTransformer subclass to convert a UIImage to/from an NSData to allow insertion/retrieval to/from a Core Data SQLite database. Howe开发者_运维问答ver, after selecting Attribute type Transformable in the Xcode 4.2 integrated Data Model Editor, there is no Value Transformer Name property to specify which transformer class should be used.

Does anyone know where this has moved to? It was there in earlier versions of Xcode.

Many thanks!

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This is from Xcode 4.1:

The (value transformer) Name box is right below Attribute Type.

By the way, I bind an NSImageView's Value binding to this attribute, and it works as desired, even without specifying a value transformer.