Try:
ToolStripButton TSBtn = new ToolStripButton();
StatusStrip.Items.Add(TSBtn);
ToolStripButton TSBtn1 = new ToolStripButton();
StatusStrip.Items.Add(TSBtn1);
ToolStripButton TSBtn3 = new ToolStripButton();
StatusStrip.Items.Insert(1, TSBtn3);
[edit]Changed to match OP code - OriginalGriff[/edit]