Send keys to window with Openbox

I'm trying to make Openbox send the Alt+Tab key combination to TeamViewer using this:

<keybind key="A-Tab">
 <action name="If">
  <title type="pattern">* - TeamViewer - *</title>
  <then><!-- Do nothing for foo --></then>
  <else>
      <action name="NextWindow">
        <dialog>icons</dialog>
        <finalactions>
          <action name="Focus"/>
          <action name="Raise"/>
          <action name="Unshade"/>
        </finalactions>
      </action>
  </else>
 </action>
</keybind>

That way Openbox won't show its own Alt+Tab menu when the TeamViewer window is focused.

The problem is that Openbox swallows the key, and I won't TeamViewer to receive the Alt+Tab key combination so it switches to the next window on the remote machine.

I need something like:

Is there a way to pass the Alt+Tab key combo to TeamViewer, something like:

  <then><action name="Send Keys">A+F4</action></then>