Add mail folder including subfolders

Hi all, maybe a stupid question, but up tons I can not manage to import a whole folder (including the subfolders) form Apple Mail to DT Pro. I get it only to work with a single folder. Can anyone give me a hint how to do this?

Using Archive Mailbox should reproduce the structure found in

Thanks a lot. Sometimes you do not see the obvious - like I did in this case. :wink:

The obvious is often the hardest thing to see.