Excluding some classes from the cobertura report doesn't work

Question

I tried to exclude some classes from cobertura as specified in this site

<cobertura-instrument todir="${voldemort.instrumented.dir}" datafile="${cobertura.instrument.file}">
    <classpath refid="tools-classpath" />
                <ignore regex=".*\.xsd" />
                <fileset dir="${voldemort.dist.dir}/classes">
                    <include name="**/*.class" />
                    <exclude name="**/client/protocol/pb/*.class"/>
                    <exclude name="**/server/http/*.class"/>
            </fileset>
        </cobertura-instrument>

but that doesn't work

help me out, pleaseeeeeeeeeeee