Getting handle of root object from c#

Hi,
             I'm trying to access Simulink from c#. 'sfroot'
command returns the handle to the root object. But, when I'm executing the
same command from c#. It's returning me the string
"simulink.root". I explicitly tried type casting this with object and
also tried creating an object thru reflection in .NET, but no success :(
   
  Here's the piece of code:
   
  MLApp.MLAppClass matlab = new MLApp.MLAppClass();
string myStr = matlab.Execute("sfroot");
   
  Am I missing something? Is there any other way?
   
  Thanks,
Ajit