To make a whole parameter required is not possible in Ivy, because you have to change the generated webservice class. This is not recommended because ivy has to regenerated the class if something changes int the associated webservice process.
To make an field of an complex attribute required you have to create an own Java class which you then use as parameter. See example Java class below which makes the field bla required.`param` *required*.
public class MyWsBean {
@javax.xml.bind.annotation.XmlElement(required=true)
private String bla;param;
...
}
The generated WSDL looks like this:
<xs:sequence>
<xs:element name="bla" name="param" type="xs:string"/>
</xs:sequence>