New to Camel, adding smtp completion notification using XML DSL

Hi I'm new to camel (so forgive me for asking dumb question). Having worked a
few examples and successfully created some test routes - I'd like to email
recipient(s) on completion. Ultimately the intent would be to email success
/ failure...but taking baby steps, just an email at the end of processing
would be enough for me to expand my understanding.

In my real code (not the pseudo below) I've successfully received an email
*but* I cannot understand how to override the email body (currently it's the
content of the message processed by direct:start - in my instance a zip
file).

I've experimented with <transform> (to transform the message/body before
emailing) but that didn't appear to work.

Any suggestions?!

Kind regards