Replicatiing .ICS files for Notes 6 email

Hello,

I'm trying to manually replicate the creation of Lotus Notes 6 meeting
invitations. I have a standalone app. that fires off emails, the text
of which is stored in a database.

Now, I want to try and format these emails to be in the format of
meeting invites, so our Notes 6 users can add them to their calendars
just like a normal invite.

Does the .ics file have to be an attachment, or can it be embedded in
the body of the mail somehow?

Thanks,

Daren