Defining New IDoc Types 
Purpose
If the IDoc types (basic types) supplied with the standard SAP System do not meet your requirements, you can define your own IDoc types.
Prerequisites
Before you define a new IDoc type, you should first check whether the basic types can be made to meet your requirements. You can display a list of the basic types and their meaning using the documentation tools in the IDoc Interface.
Process flow
Preparation
New IDoc types should be defined within the scope of a customer extension within which customer segments are appended to an existing basic type. For more information, see Important Terms and Design Guidelines and Formatting Rules for Creating New Segments.
When creating a customer extension, you should first list the segments which are required. You may have to develop your own segments, in which case you should follow these guidelines. See the Design Guidelines for Creating New IDoc Types
Definition
To define your IDoc types, you should use the development tools in the IDoc Interface, which are described in the following sections:
· The Programming Interface (API) for Defining IDoc Types
Automatic definition of IDoc types is only required in special cases. You can generally skip this section.
Check lists: From definition to implementation
The following two checklists describe a general procedure from definition to implementation for new IDoc types in the following cases:
· Defining and Using a New Basic Type