<instructions>
    <customExecutes>
        <customExecute step="install" schedule="pre" exeName="[NISHAREDDIR]NI WebServer\installer\unloadServiceHelper.exe" arguments="stop niSvcLoc" condition="1" wait="n" ignoreLaunchErrors="y" />
        <customExecute step="uninstall" exeName="[NISHAREDDIR]NI WebServer\installer\unloadServiceHelper.exe" arguments="stop niSvcLoc" condition="1" wait="n" ignoreLaunchErrors="y" />
    </customExecutes>
</instructions>