How to add security permissions in build.xml using Ant Web Start

I am not very familiar with java build tools such as Ant. We have an old java web start application and now with the new security requirements for RIAs I have to add a security tag to my build.xml But I can't figure out how to do it. I am using ant deploy to build my app. And I am also using ant-jnlp-war (I really can't figure out where this ant-jnlp-war is used) The relevant part of my build.xml is as the following:

<target name="pack" depends="buildinfo,dist,sign">
    <jw:jnlpwar
        tofile="${war}/lmc.war"
        title="Company Management Console"
        vendor="Company Teknoloji"
        codebase="dummy"
        signStorepass="secret"
        signAlias="labris">
            <jw:description>Company Management Console</jw:description>
            <jw:description kind="short">LMC</jw:description>
            <jw:shortcut desktop="true" menu="true" submenu="Company Management Console"/>
            <jw:j2se minVersion="1.5" args="-Xmx128M" />
            <lib dir="${dist}/lib">
                <include name="**/*.jar"/>
                <exclude name="client.jar"/>
            </lib>
            <lib dir="${dist}/modules">
                <include name="**/*.jar"/>
            </lib>
            <jw:application mainclass="com.idealteknoloji.lmc.client.ClientManager" jar="${dist}/lib/client.jar"/>
    </jw:jnlpwar>
    <exec executable="./make-client-packages"/>
</target>

How and where can I add the security attribute as sandbox.