Creating Service Order from Campaign

Hello Guru's

I m really stuck presently with my Task.

My scenario is, we have modified service order transaction (zsrv), and this service order has been modified by adding custom developed classification that we assign every time we create service order manually. I have to create same service order from campaign execution.

At the same time when we create campaign, this classification is assigned in campaign screen and stored in bespoke table. Then i have to create service order automatically from campaign when executed.

So can any one help me on this scenario. what BADi i have to use, what is the best approach for this. How i can pass the classification of campaign to service order.

please help me

thank you

shankar