[vdr] calling MainMenuAction() from an other plugin

[Patrick Fischer]

Hello
I want to show an special message on the screen. (with image, buttons,...)
My idear was to write an second Plugin which have a MainMenuAction which 
shows the message on the OSD. The param will be set by a service which 
was called before I call

cPlugin *Plugin = cPluginManager::GetPlugin("myShowMessage");
if (Plugin)
    Plugin->MainMenuAction();


The problem is that I need to call this code from an background thread, 
so the called plugin can't handle the osd.

Mar 28 10:27:49 localhost vdr[7282]: ERROR: attempt to open OSD while it 
is already open - using dummy OSD!
Mar 28 10:27:49 localhost vdr[7282]: ERROR: OSD opened without closing 
previous OSD!

Is there any possibility to call the Plugin with full osd support?