Sorry. I have a much trickier transformation mapping which uses a similar
structure that I'm getting the same error with, and I was hoping that
getting help with this simpler mapping would lead me in the right
direction on the other issue. However, it turns out that the error came
from the tricky mapping all along and had nothing to do with the enum
mapping.
I'll probably be back with questions about the other mapping soon. :P
/Matti