Hi Gavin,
I do not use pop3 but the incoming e-mail server as described here: Direct-delivery incoming email for self-hosted sites
Regarding your 3 steps:
1 there is no mailbox so I cannot login to it, the mail should be directly picked up by the service in the additional container right?
2 is set manual polling (instead of pop3)
3 not sure i quite understand this step
Thanks,
Justin