Setting Task status to InProgress Programmatically

Hi,

I am using VS 2010 Sequential workflow.

I am trying to set the workflow status to InProgress, but not able to. I have tried for approve and reject as below which works fine, but how to set the InProgress status?

   Hashtable taskHash = new Hashtable();
 // Approved
taskHash[SPBuiltInFieldId.TaskStatus] = "#";

 // Rejected
taskHash[SPBuiltInFieldId.TaskStatus] = "@";

How to set the workflow status to be "In Progress" programmatically?

Thanks