java.lang.IndexOutOfBoundsException: only START_TAG can have attributes TEXT seen

we found a problem with using nillable="true" and optional="true" on
the very same value tag.

think about the following example binding:
<?xml version="1.0" encoding="ISO-8859-2"?>
<binding>
<mapping name="Data" class="usageoptreq.UsageOptReqData" ordered="false" flexible="true">
<value name="optional1" field="optional1" nillable="true" usage="optional"/>
<value name="optional2" field="optional2" nillable="true" usage="optional"/>
<value name="optional3" field="optional3" nillable="true" usage="optional"/>
<value name="optional4" field="optional4" nillable="true" usage="optional"/>
</mapping>
</binding>

we get the following error during runtime (compilation works fine):

java.lang.IndexOutOfBoundsException: only START_TAG can have attributes TEXT seen ...<optional1>OO Optional1<... @6:26
at org.xmlpull.mxp1.MXParser.getAttributeValue(MXParser.java:927)
at org.jibx.runtime.impl.XMLPullReaderFactory$XMLPullReader.getAttributeValue(XMLPullReaderFactory.java:395)
at org.jibx.runtime.impl.UnmarshallingContext.getAttributeValue(UnmarshallingContext.java:356)
at org.jibx.runtime.impl.UnmarshallingContext.attributeBoolean(UnmarshallingContext.java:1881)
at usageoptreq.UsageOptReqData.JiBX_binding_unmarshal_1_2(UsageOptReqData.java)
at usageoptreq.JiBX_bindingUsageOptReqData_access.unmarshal()
at org.jibx.runtime.impl.UnmarshallingContext.unmarshalElement(UnmarshallingContext.java:2537)
at org.jibx.runtime.impl.UnmarshallingContext.unmarshalDocument(UnmarshallingContext.java:2680)
at usageoptreq.UsageOptReqTest.testCompileAndTransform(UsageOptReqTest.java:34)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
at java.lang.reflect.Method.invoke(Method.java:324)
at junit.framework.TestCase.runTest(TestCase.java:154)
at junit.framework.TestCase.runBare(TestCase.java:127)
at junit.framework.TestResult$1.protect(TestResult.java:106)
at junit.framework.TestResult.runProtected(TestResult.java:124)
at junit.framework.TestResult.run(TestResult.java:109)
at junit.framework.TestCase.run(TestCase.java:118)
at junit.framework.TestSuite.runTest(TestSuite.java:208)
at junit.framework.TestSuite.run(TestSuite.java:203)
at org.eclipse.jdt.internal.junit.runner.junit3.JUnit3TestReference.run(JUnit3TestReference.java:128)
at org.eclipse.jdt.internal.junit.runner.TestExecution.run(TestExecution.java:38)
at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.runTests(RemoteTestRunner.java:460)
at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.runTests(RemoteTestRunner.java:673)
at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.run(RemoteTestRunner.java:386)
at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.main(RemoteTestRunner.java:196)

so far the only workaround we found is either not to use
nillable="true" or not to use optional="true". you can guess that this
is not what we wanted

Explanantion for the attached zip archive:
run the ant build file in srcipts/, then call the unit test. this produces the error.