Batch stock to Saleorder

Here i have customers material, after receiving the material from the customer i am keeping it in stock

After few days only customer will tell what design should be printed on that material

(For eg: customer have sent 5000 mtrs for cloth, after few days he will send the design for only 2000 mtrs, 2 different colors (Blue, Green each 1000 mtrs) 2 line items in sale order) at that time we are raising the salesorder)

In this case i have splitted the cloth 2000 mtrs into 2 batches(1000bat1,1000bat2) each 1000 mtrs(Remaining 3000mtrs will be in stock)

Now how to assign this for the salesorder