can you tell me why this badi is used
Using this BAdI you have the option of choosing either a active vendor list i.e, having a list of vendors for certain material, or the the available source of supply as the SOS for going with the sourcing of shopping cart or limit shopping cart.
This you can do my selecting the parameter AVL_DET. If you want the active vendor list as the SOS then you can set this parameter (AVL_DET = 'X').
If you want to know more about vendor lists , go through the following link: