I couldn\'t find anything about the BodyType-Property (beside the MSDN), especially nothing about the meaning of each integer. So I created messages with BodyTypes = 0...100
Even though the question and answer are two years old, it sometimes helps to dig through the C++ documentation when dealing with obscure MS API's. This is no exception.
PROPID_M_BODY_TYPE
Describes the body types, and what the body should contain.
What continues to be unclear to me is weather these values should have custom values when creating a custom format handler.
Maybe there are even more BodyTypes and someone could add them