Resume app when tapping a received toast notification
===

I'm trying to open my app when a user taps the received toast notification. I have setup the server to post this message:

    <?xml version="1.0" encoding="utf-8"?>
    <wp:Notification xmlns:wp="WPNotification">
      <wp:Toast>
        <wp:Text1>Message</wp:Text1>
        <wp:Text2>Resume application</wp:Text2>
      </wp:Toast>
    </wp:Notification>

When my app is in the background (or fully closed) I'm getting a notification as expected but when I tap the notification it will just open the app and run my main page.

Instead, I would like it to:

* if app closed => open main page (as it does now)
* **if app in background => resume app**

I have tried with the "wp:Param" argument as well with both a absolute url to a page (which is not what I want) and by starting with "?" (to indicate it should transfer that parameter to the main page).