Using the following XML Schema features can cause maps to display or transform incorrectly, and can cause validation warnings:
Limitations to mapping rules might not allow you to correctly define transformation requirements for nodes within a choice. The guaranteed status of mapping rules involving choice structures might be incorrect. Transformations to destination schemas that have choice structures might incorrectly include all choices.
Elements that allow mixed content can contain both data and other nodes. These nodes display correctly and can be mapped. However, transformation of messages with mixed content nodes might not be complete.
You cannot create a map with unlimited levels of recursive elements. You can specify mapping rules for no more than five recursive levels.
Substitution groups support deriving elements by extension. Using substitution groups in an XML Schema to extend an xs:anyType element to different types of elements is not supported. For example, extending an xs:anyType element to either an element based on a simple type or an element based on a complexType is not supported.
The ability to derive complex types by extension using type substitution is supported. For more information, see Selecting a substitution type and Selecting a Substitution Type for Variables.
The Mapping Editor does not provide information about elements that have unique, key, or keyref constraints and mapping rules do not evaluate.