Thanks to everyone who pointed me to single piece "box with lid" models. Even though some of the models had similarities, none of them was identical to my box, most of them are more complicated to fold. So I've taken the liberty to draw the diagrams.
You can find the diagrams for my Box with Lid on the Origami Austria homepage: http://www.origamiaustria.at/en/diagrams.php?lang=2#d41 Nice Greetings Anna Kastlunger from Vienna, Austria
