Mime - just need a 'wee' pointer

Been finding out the joys of doing MIME with Domino. Actually thanks to various posts I am nearly there.

My main problem is when dealing with inline graphics - I can get them to work but not with an attachment as well. This relates to the fact that the composed MIME does not have enough headers.

What I should have is Content-Type: multipart/mixed; with a boundary and then another header with Content-Type multipart/related.

I seem to be able to do either or!

How do I group together various Child Entities so that they are multipart/related leaving attachments as multipart/mixed in terms of the boundry seperator?

Thanks!

Ian