I did something like this :
I put the executable file in a directory, the data structure in a subdirectory named "Setup"
As I launch the application from a main program which point to a Working directory ( say "..\something\DATA" ), it checks if exist the subdirectory
..\data\MyAppData, if it doesn't I create the directory and copy the Files from the "Setup" directory.
Now I could check if the Database version is the same, if not i could copy the new data structure into a temp directory, append data from the old tables , then copying the files and the database from the temp directory to "MyAppData".

It should work. I was thinking about another thing.
How can I run my Application in a Private Datasession ?
I was trying to use Session Obiect but I still don't understand how to use it....
:-) thank you