VB使用TEECHART工具绘制实时曲线怎么实现？

若横坐标是点的话，比较好实现，用MAX,MIN 属性就能做出，如下：
Private Sub Timer1_Timer()
Dim a As Integer
b = b + 1
k = Rnd(100)

TChart1.Series(0).Add k, b, vbBlue

With TChart1
            .Scroll.Enable = pmHorizontal 'permit manual scrolling horizontally only.
            .Axis.Bottom.Automatic = False
            .Axis.Bottom.Maximum = b
            If b < 10 Then                             
                .Axis.Bottom.Minimum = 0
            Else
                .Axis.Bottom.Minimum = b - 10
            End If
            .Repaint
        End With

End Sub

横坐标是时间，怎么实现？
看过dephi里面有一种方法：
if series1.count>100 then
charttool1.axis.scroll(1.0,true)
就能移动横坐标

关键是在VB里面这个属性和方法怎么实现啊？