Defining Mapping Modules 
Defining Mapping Modules
Under Mapping Modules the individual function modules are defined that contain the mapping from the source data structure to the target data model when loading data (for example, from R/3 to CRM). In many cases the data models of the source and target systems are different so that mapping is implemented in one function module. The values are delivered by SAP and should not be changed. You only have to make new entries for customer-defined objects.
For each Customizing object with an assignment to a BDoc type you have to define the mapping function module MAP_BAPIMTCS_TO_CUSTOMIZING. This ensures that Customizing data is assigned directly to the specific tables of the mobile application. If no BDoc type exists and/or data is to be assigned directly in CRM tables, you can create your own mapping module.
The fields have the following meanings:
If several mapping modules are to be run through, their call up sequence should be given.
Note: the field is mapped internally to the key field CRM_VERS. Normally it can remain empty.
The data is stored in table SMOFSUBTAB.