Indexes defined in XML mapping files are not considered for Metadata and SchemaExport in the following cases:

• Defined in a property, e.g. <property name="name" index="person_name_index" type="string"/>
• Defined in a many-to-one, e.g. <many-to-one name="personGroup" foreign-key="person_persongroup_fk" index="person_persongroup_index" class="PersonGroup"/>

In Version 4.3 the index creation worked fine.