characteristics based planning

Hi All,

Please suggest me how we can check the availablity of stock in the system based on your characteristics? lets say you have a car as a variant material (KMAT) i have a char as colour so i have a stock of car which is of red colour of 50 and i have a requirement of car which is of blue colour of 50 so the system should create a planned order as ther is no stock of car which is of colour blue.How the ATP also works on the characteristcs base?

Thanks

Vishnu