Paper UI - Command format for setting Sonos volume?

Hello

I have created a rule in Paper UI (rule engine experimental). When the rule fires, it is supposed to set the volume of a Sonos speaker to 40%, but the log gives the following error. I have tried entering both 40, 40.0 and 40%. What would the correct format be in this case?

17:13:26.178 [ERROR] [ome.core.thing.internal.ThingManager] - Exception occured while calling handler: org.jupnp.model.types.InvalidValueException: Can’t convert string to number or not in range: 40.0
java.util.concurrent.ExecutionException: org.jupnp.model.types.InvalidValueException: Can’t convert string to number or not in range: 40.0
at java.util.concurrent.FutureTask.report(FutureTask.java:122)[:1.8.0_121]
at java.util.concurrent.FutureTask.get(FutureTask.java:206)[:1.8.0_121]
at org.eclipse.smarthome.core.common.SafeMethodCaller.callAsynchronous(SafeMethodCaller.java:188)[98:org.eclipse.smarthome.core:0.9.0.b4]
at org.eclipse.smarthome.core.common.SafeMethodCaller.call(SafeMethodCaller.java:81)[98:org.eclipse.smarthome.core:0.9.0.b4]
at org.eclipse.smarthome.core.common.SafeMethodCaller.call(SafeMethodCaller.java:65)[98:org.eclipse.smarthome.core:0.9.0.b4]
at org.eclipse.smarthome.core.thing.internal.ThingManager.receiveCommand(ThingManager.java:369)[105:org.eclipse.smarthome.core.thing:0.9.0.b4]
at org.eclipse.smarthome.core.items.events.AbstractItemEventSubscriber.receive(AbstractItemEventSubscriber.java:46)[98:org.eclipse.smarthome.core:0.9.0.b4]
at org.eclipse.smarthome.core.internal.events.OSGiEventManager$1.call(OSGiEventManager.java:192)[98:org.eclipse.smarthome.core:0.9.0.b4]
at org.eclipse.smarthome.core.internal.events.OSGiEventManager$1.call(OSGiEventManager.java:1)[98:org.eclipse.smarthome.core:0.9.0.b4]
at org.eclipse.smarthome.core.common.SafeMethodCaller$CallableWrapper.call(SafeMethodCaller.java:179)[98:org.eclipse.smarthome.core:0.9.0.b4]
at java.util.concurrent.FutureTask.run(FutureTask.java:266)[:1.8.0_121]
at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1142)[:1.8.0_121]
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:617)[:1.8.0_121]
at java.lang.Thread.run(Thread.java:745)[:1.8.0_121]
Caused by: org.jupnp.model.types.InvalidValueException: Can’t convert string to number or not in range: 40.0
at org.jupnp.model.types.UnsignedIntegerTwoBytesDatatype.valueOf(UnsignedIntegerTwoBytesDatatype.java:27)[162:org.jupnp:2.2.0]
at org.jupnp.model.types.UnsignedIntegerTwoBytesDatatype.valueOf(UnsignedIntegerTwoBytesDatatype.java:1)[162:org.jupnp:2.2.0]
at org.jupnp.model.VariableValue.(VariableValue.java:54)[162:org.jupnp:2.2.0]
at org.jupnp.model.action.ActionArgumentValue.(ActionArgumentValue.java:32)[162:org.jupnp:2.2.0]
at org.jupnp.model.action.ActionInvocation.setInput(ActionInvocation.java:130)[162:org.jupnp:2.2.0]
at org.eclipse.smarthome.io.transport.upnp.UpnpIOServiceImpl.invokeAction(UpnpIOServiceImpl.java:296)[184:org.eclipse.smarthome.io.transport.upnp:0.9.0.b4]
at org.eclipse.smarthome.binding.sonos.handler.ZonePlayerHandler.setVolume(ZonePlayerHandler.java:1347)[183:org.eclipse.smarthome.binding.sonos:0.9.0.b4]
at org.eclipse.smarthome.binding.sonos.handler.ZonePlayerHandler.setVolumeForGroup(ZonePlayerHandler.java:1363)[183:org.eclipse.smarthome.binding.sonos:0.9.0.b4]
at org.eclipse.smarthome.binding.sonos.handler.ZonePlayerHandler.handleCommand(ZonePlayerHandler.java:241)[183:org.eclipse.smarthome.binding.sonos:0.9.0.b4]
at org.eclipse.smarthome.core.thing.internal.ThingManager$4.call(ThingManager.java:372)[105:org.eclipse.smarthome.core.thing:0.9.0.b4]
at org.eclipse.smarthome.core.thing.internal.ThingManager$4.call(ThingManager.java:1)[105:org.eclipse.smarthome.core.thing:0.9.0.b4]
… 5 more
Caused by: java.lang.NumberFormatException: For input string: "40.0"
at java.lang.NumberFormatException.forInputString(NumberFormatException.java:65)[:1.8.0_121]
at java.lang.Long.parseLong(Long.java:589)[:1.8.0_121]
at java.lang.Long.parseLong(Long.java:631)[:1.8.0_121]
at org.jupnp.model.types.UnsignedVariableInteger.(UnsignedVariableInteger.java:62)[162:org.jupnp:2.2.0]
at org.jupnp.model.types.UnsignedIntegerTwoBytes.(UnsignedIntegerTwoBytes.java:27)[162:org.jupnp:2.2.0]
at org.jupnp.model.types.UnsignedIntegerTwoBytesDatatype.valueOf(UnsignedIntegerTwoBytesDatatype.java:25)[162:org.jupnp:2.2.0]
… 15 more