Has anyone been able to compile an XLS decision table into a package via an Ant build script?

I've scouring the documentation on the Drools Ant Compiler Task (what little I could find) and I can't find any documentation on hw to pass configuration into the ant task for things such as compiling XLS decision tables.

Without a configuration entry, when I try and run the build script referencing an excel file, it fails with the following error:
Buildfile: C:\Documents and Settings\Adam\workspace\RivaDroolsExperiment\build-5.1.xml
compileArtifacts:

BUILD FAILED
C:\Documents and Settings\Adam\workspace\RivaDroolsExperiment\build-5.1.xml:21: RuleBaseTask failed: null
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I suspect this message is because the compiler task is failing with a null pointer exception, which it throws when you don't provide it with a configuration file. I am running
the build3423-rev29890-20091102-1042 Drools 5.1 Snapshot.

The relevant snippet from the build script:
<target name="compileArtifacts">
        <compiler srcdir="${projectPath}src/main/rules" tofile="${projectPath}target/experiment.pkg" binformat="package" bintype="knowledge" classpathref="model.classpath">
            <include name="Sample.xls" />
        </compiler>
    </target>
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Thanks,
Adam