There has been some work on message parsing and attachment handling in recent SVN versions. You might want to give a recent (Revision 451 or newer) version a try. There are links in the SVN forum here with snapshots you can download to use, and there are upgrade instructions on the Wiki.
If you get stuck or need help, post in the SVN forum and someone should be able to lend a hand.
If the messages still do not appear right with a recent SVN version, it would help a lot of we had copies of messages that are not working, so that the problem can be properly diagnosed.