Hi George,
In my opinion it should work as long as you are using an appropriate Package (transportable, connected to a transport layer).
If you have more than 1,000 DataSources, please do not forget to remove the restriction on number of objects (it's 1,000 I believe).
If you go to the menu, choose Select Subtree and after that via the menu Reassign, you should be able to change the Package for all DataSources in one go.
Please try it again.
Best regards,
Sander