drools-ant-4.0.7, DroolsCompilerAntTask, classloader mixup leads to ClassCastException if drools-compiler.jar part of classpathref

drools-4.0.7:

Original error in build.xml:
/home/juergen/workspace/eclipse/kusss-dev/build.xml:777: RuleBaseTask failed: Unable to load dialect 'org.drools.rule.builder.dialect.java.JavaDialectConfiguration:java'

Traceback to:
org.drools.compiler.PackageBuilderConfiguration, line 154+:
Class cls = classLoader.loadClass( dialectClass );
DialectConfiguration dialectConf = (DialectConfiguration) cls.newInstance();

cls is org.drools.rule.builder.dialect.java.JavaDialectConfiguration, but loaded via classloader given in drools compile ant task property classpathref, while DialectConfiguration is loaded via ant tool classpath used for taskdef
-->
java.lang.ClassCastException: org.drools.rule.builder.dialect.java.JavaDialectConfiguration

interim fix:
make sure drools-compiler.jar is not in classpath of classloaderref

suggested fix:
Class cls = DialectConfiguration.class.getClassLoader().loadClass( dialectClass );