We had a bit of software once that ran part locally and part on a web server for frontend access. It had a facility to create a secure connection from the local host to the web server, upload the files and the web server software then imported the data. In essence like a manual FTP up to the server and then a manual import from the server....but all automated.
So, may thinking, if there were some tool created that could convert then transfer to SM and then SM import....even if the tool asked certain details such as email account / password etc. so the import could take place and the configuration could be imported by SM.
I think that's really the only way this is going to happy apart from a manual .pst conversion tool....but then we have the issue that it might convert the emails but not config. Probably losing date stamps etc. Saying that though, we have used a few .pst conversion tools when going back and forth from Mac to Windows so cannot see any reason why there can't be one from .pst to SM require format/folder structure then all we would need to do is manually FTP to the Domains folder after creating the blank mailbox.