Opening old .OST files

Does anyone know how to open and old Ofline folder (OUTLOOK.OST) created with Exch 5.5 and Outlook 98. Message says “the file was created for a different account”.
The original user’s account name will not work. The NT server is now W2K and the Exch Server is now Exch 2000. The folder is believed to contain useful info. I could build an Exch 5.5 server if REALLY needed. But, I suspect this wont work as this will still give a different SID for this account.