--- CAN BE CLOSED ---
After no one was even reading this post (in 12 days), I got help in the IRC. (almost instantly!)
Fact is, I can't do what i had tried.
The only way is, to store the items in an chest/drone to swap itemstacks in an database-upgrade with an inventory-controller, or use multiple databas-upgrades.
Maybe in the future there is a way to use an itemstack (which u can get from an AE-Interface itself) and use this to change a database-upgrade or the interface/exportbus.
BlankWolf