[Haskell-beginners] Text.JSON.JSON instance for Data.Text.Text

Hej, I'm trying to create a JSON instance for Data.Text.Text. The CouchDB package uses Text.JSON, otherwise I would've considered using Aeson … This is what I've got so far: http://hpaste.org/64281 showJSON and readJSON work with this, but fromJSON and toJSON from Text.JSON.Generic don't. I'm not really sure how to 'tell' these functions how to use my instance. Any ideas? :] Vincent