I changed in the table "eav_entity_text" my order "increment prefix" into "ON-" and in "increment_last_id" i set it to "ON-10001". Also i changed in table "eav_entity_type" the "increment_pad_length" of orders to "5". But when i now make a order everytime my store adds a "1" to the order increment ID.
For example: - First order: 10002
- Second order: 110003 - Third order: 1110004 and so on...
I dont know whats going wrong? It wont use my prefix for orders, for invoices it works well...