Outlook stores files and account information seperately.
It stores them in different places for different versions of Outlook.
It stores them in differnt places for different operating systems.
Why bother to standardize, right?
So you're program will have to react correctly to all these parameters.
A list of file locations (not accounts, but outlook files) can be found
here.
The article points out that account data is stored in the Windows registry.
Google found an
article and VB code that reads the registry for account info.
Dissecting the VB for reading should get you all the locations and values to expect. So your program would write to those locations.
Good luck!