Restoring Outlook 2007 on XP

I have been asked to restore some data from a dodgy hard disk. I have been able to restore all data except the outlook files. There are not .PST files on the drive, nor on his mirrored drive or his backup.

I reinstalled outlook for him, on a new drive, and he is using it and there is still no .PST files on his new drive.

Outlook - Outlook 2007

O/S - XP

Are the emails stored in a file other than PST?

I have looked in C:\Documents and Settings\%username%\Local Settings\Application Data\Microsoft\Outlook\

and under Roaming data and can find outlook files but not .PST files.

Any suggestions greatly appreciated.

Thanks