Tried that before… no good. Before sending out this plea, we already added NS_POLICY (our own custom namespace) and NS_PORTAL to that variable array. No dice.
I know that making changes to this variable will turn the factbox on or off for namespaces already in it (tried successfully that on NS_TEMPLATE), but it does not respond to our custom namespaces.
Wait, I know this one! Look at the installation manual on SMW's website, here:
And find therein the variable $smwgNamespacesWithSemanticLinks. This will allow you to specify the namespaces the engine will search for semantic information.
Hope that helps!