How do I add new fields to the 'Customer Data' tab under the BP
You can do this using transaction EEWB. This is the Easy Enhancement Workbench.
within this, you can use the wizard which will guide you through a step by step process to add the fields you need. Basically, there are 2 ways to add new fields :
1. Add new fields - this adds fields to table BUT000, but places the fields on a new tab called 'Customer Data'
2. Add new attributes table - creates a new table and links it to BUT000 using the partner number.
Hope this helps you.