I've enabled MAPI for my own account, went pretty smoothly until I received a rather important email last night which had an attachment.  The issue is that in webmail the attachment is available and downloads fine, in Outllook the messages lists shows that the email has an attachment, but the email details pane does not show the attachment and there's no way to download it.

Outllook Version:

Outlook Message List - note there are two emails with attachments showing in the list of messages.  Here is one from earlier which DOES work normally:

And here's the more recent message which shows in the message list that there is an attachment but when viewing the message it's not there:

And that same message within the webmail showing that there's an attachment in the attachment tab, and that it can be downloaded just fine: