My elderly neighbour has bought a new PC running Win 8.1 to replace his 10-year old XP machine, and I have been setting up his new machine and transferring data from the old one.

I need help with a problem transferring email messages.  He was using Outlook 2003 on his old machine but does not wish to splash out on Outlook 2013.  I have therefore set up his email in the Mail app and plan to install Live 2012 mail for him.  Because he plans to buy a tablet in the the near future I set up his Sky email account as IMAP rather than the POP account he was using on his old PC.  Unfortunately this means that his existing messages no longer show up and are effectively "stranded" on his old machine.

I have been considering how to get his old messages on to his IMAP account on the new PC, as neither the Mail app nor Live Mail will allow me to import either the csv files or the pst file that I exported from his old PC.  I have come up with a potential solution and would appreciate input from the Community on whether it might work.  I have Office for Mac 2011 on my iMac but do not use Outlook as I prefer to use the native Apple apps.  My idea is to set up his Sky email account in my Outlook (as an IMAP account), open the pst file that I exported from his old PC, and bring in the old messages into his IMAP inbox.  I am assuming that the messages would then appear on his new PC when he next checks his email.  I could then delete his account from my Outlook.

A cunning plan or a lemon?