ServiceM8 emails

My client is using the Rest API to connect ServiceM8 to their local software platform. While I have the basics working, I am stumped on emails.

The emails that are sent out of ServiceM8 are stored in the diary and are tagged as emails. They are using the inbox to do this.

What they want me to do is retrieve the emails as shown in the diary, and if possible write emails from their system into to the diary. This would bypass any SMTP/IMAP/POP functionality. By the time I am doing this, it has already been sent, or received. I just need to get text into, or out of, the diary, and have it marked as email in the diary.

So, what am I missing? I fear it might be really simple! How do I read an email from, or post an email to, the diary?

TIA

Ken Moorhead