Making a DominantSpotLight cast dynamic shadows only

[Minos]

I've been trying with no success to force a dominant spotlight actor cast dynamic shadows only. It looks alright on the editor viewport (with real time dynamic shadowS) but as soon as build lighting and hop into the game it turns into static light! Anyone knows how to do that?

[Lamont]

This might help:

http://udn.epicgames.com/Three/DominantLights.html