Addition of new item during Sales delivery

Hi Gurus,

1. While creating a delivery, it is possible to add a new line Item ( a new material ) to the delivery vl02n, even though the material may not be present in my preceeding Sales Order. Why does SAP allow that ?

How can i stop it from doing that, i guess copy control tweaking

2. Also , its a client requirement that we be able to create deliveries for a future date, & the will do Goods Issue when the date has come. They just want to create deliveries & keep . But of corse, it gives me the "schedule line not available for the date error", though the material is there. Any way to get around that ?

Help appreciated

Thanks