This XSD missing the "encoding" attribute in http://izpack.org/schema/5.0/izpack-installation-5.0.xsd in <xs:complexType name="resourcesType"> in <xs:element name="res" minOccurs="0" maxOccurs="unbounded">.
This attribute is used in class com.izforge.izpack.compiler.CompilerConfig.
This attribute is very important because if it does not present then resource files will be ruined if they contain non-ASCII characters and have parse="yes" attribute.
And wiki knows nothing about this attribute:
I think it also should be fixed.