Can you import an .OST file

Cached files are local in our hosted environment. I want to migrate mailboxes to a new internal server by importing the .ost files. But that does not work with the GUI import in Outlook 2003 client. Says this is not a .pst file. Tough luck.

Any reason to think that exmerge or something else would be able to import the .ost file.

Saves me time from creating backup .pst files.

thanks