You can modify generated classes either by using hints in the XSD or by using a binding file although I'm not familiar with getting binding files working with the eclipse generator (I usually use the maven plugin). Try editing the XSD/WSDL like this
<xs:complexType name="Type">
<xs:sequence>
<xs:element minOccurs="0" name="Übersicht">
<xs:annotation>
<xs:appinfo>
<jaxb:class name="Ubersicht"/>
</xs:appinfo>
</xs:annotation>
</xs:element>
</xs:sequence>
</xs:complexType>