Step 1 - Add following to workflow.xml file
<ExtendedStatusColumnValues>
<StatusColumnValue>Need Restart</StatusColumnValue>
<StatusColumnValue>Waiting for Approval</StatusColumnValue>
</ExtendedStatusColumnValues>
Step 2 - Use SharePoint Workflow SetState shape.
Bind a field workflowState to its State Property.
MethodInvoking - setWorkflowStatus_MethodInvoking
private void setWorkflowStatus_MethodInvoking(object sender, EventArgs e)
{
//// SPWorkflowStatus.Max for "Need Restart"
//// SPWorkflowStatus.Max + 1 for "Waiting for Approval"
this.workflowState = (int)SPWorkflowStatus.Max;
}
Step 3 - For an existing feature, deactivate - uninstall - install - Activate the feature for the above changes to reflect.