OK, so then I did use SimpleMail for MorphOS 0.35 without realizing it (the About box does not say clearly what architecture you are running; later I found the official page without 0.35 enlisted so I thought I was running the 68K version...).

In any case, I don't have luck with email.

SimpleMail cannot send email to all domains using IMAP.
Yam always tries to download all 4000 messages on each startup (POP + don't delete; IMAP is not supported).

Support for IMAP in YAM was announced for 2.6, I saw it on their site.

I guess the next step is to write directly to SimpleMail developers with my problem and to wait for YAM 2.6. In the meantime maybe I can try to see if SimpleMail works somehow in POP mode for me...

Since OWB also does not work with MobileMe, I cannot use MorphOS for any emailing right now