How to return an "OUT" parameter in SmartDevices Genexus Ev3 U1?

Develop with Genexus Smart Devices Ev3 U1 for Android.

I want to develop a Father screen that, when clicking a button, opens the Son screen, where the user selects an item on a grid and returns to the Father displaying the clicked item.

But it does not return the "out" parameter of the child.

See how I'm trying:

In the " Parent " panel there is a button with the event below:

Event 'Adicionar Lugar'
Composite
pnPromptCota.Call(&addLugVCOTA_COTACODIGO)
TextblockLugarDs.Caption = &addLugVCOTA_COTACODIGO.ToString()
Interop.Msg('&addLugVCOTA_COTACODIGO= '+&addLugVCOTA_COTACODIGO.ToString().Trim())
EndComposite
Endevent

In the " Son " Panel (the Selection Prompt) has a grid with event Tap:

parm(
    out: &VCOTA_COTACODIGO
    );


Event VCOTA_COTACODIGO.Tap
&VCOTA_COTACODIGO = VCOTA_COTACODIGO
SDActions.Return()
Endevent

But when returns, it brings zero code (in "Interop.Msg ....").

For me, it does not make sense, it seems all right, just like I would in Web programming with Genexus.

What can I change to make the OUT return?

I await return. Thanks!

Note: I have tried only the "return" instead of "SDActions.Return ()" and it does not work either.