Sent sub-folder missing from imap account exported as outlook datafile

Hi everyone,

I recently exported the full folder of an IMAP account in *.pst using outlook 365. I also kept the original *.ost file. When I open the *.pst in outlook, I only see Inbox, Outbox, and Deleted. I do not see the sent sub-folder. Same when I open the *.ost file with "OST and PST viewer" freeware. I have the feeling that it's because the original account was IMAP (it worked fine with older pop accounts). The *.pst file has the same size at the *.ost file. Any idea how I could see the sent sub-folder? The original imap server is no longer working so I can't create a new imap account in outlook. Re-creating the original IMAP account is not really a long term solution either since we migrated to a new microsoft exchange server and outlook won't let me have 2 accounts with the same address. I spent 2+h on google and couldn't find any solution.  Thank you! Any idea is welcome.