Open channel analysis with 2009 Flow Simulation

I'm a newbie to 2009 Flow Simulation and am trying toevaluate models under partially submerged, gravity flow conditions- i.e. open channel flow. We bought this software with theunderstanding that this type of analysis was possible. However,when I set up the boundary conditions the thing runs as if themodel is fully submerged regardless of flow. All of the tutorialsand examples I've seen so far only address systems flowing full. Ifound one post that seemed to indicate others having troubleresolving a water/air interface with 2008 FloWorks. Can 2009 FlowSimulation do this somehow?SolidworksFlow Simulation