Cross Selling - User exits / Customer exits
I am working on Cross Selling scenario, done the configuration part and " I have sales orders placing from web to SAP so --> I need to automate these 2 steps using an user exit / customer exit in standard SAP program while creating the SO
1. Entering the sub item quantity (copying from main item and past it in to sub item)
2. Click on Copy.
...I need the list of user exits/ customer exits related to the above scenario, can some one provide the relevant one..