使用mailcore解析多部分电子邮件

I am new to mailcore. I am using it in objective-c, OS X, to parse email. I have an email I am trying to parse that is structured as a multipart/related. The first part of the multipart/related is a multipart/alternative. The multipart/alternative contains a text/plain part and a text/html part. Following that, the multipart/related contains a number of b64 encoded image/gif parts. When I use MCOMessageParser to parse this email, it returns a multipart/related as the main part, but the multipart/related contains only one part, which is text/plain and it consists of everything in the entire message as one big text blob. Can anyone tell me what I am doing wrong?I am new to mailcore. I am using it in objectiv