powershell无法向Excel图表添加多个图例条目（系列）

我有一个问题，通过powershell向excels图表对象中的seriescollection添加多个系列，这里是我的代码：

[threading.thread]::CurrentThread.CurrentCulture = 'en-US'

$excel = New-Object -comobject Excel.Application

$workbook = $excel.workbooks.add()

$datasheet  = $workbook.Worksheets.Item(2)
$chartsheet = $workbook.Worksheets.Item(1)

[datetime] $startDate  = "2012-11-29 00:00:00" 
[datetime] $finishDate = "2012-12-07 00:00:00"
[datetime] $dayCounter = $startDate

$startRow = 2
$startColumn = 2

$columnCounter = 2
$rowCounter = 2
while ($dayCounter -le $finishDate)
{
  $datasheet.Cells.Item($rowCounter, $columnCounter) = $dayCounter.ToShortDateString()
  $datasheet.Cells.Item($rowCounter+1, $columnCounter) = $columnCounter
  $datasheet.Cells.Item($rowCounter+2, $columnCounter) = 2 * $columnCounter
  $columnCounter++
  $dayCounter = $dayCounter.AddDays(1)
}

$datasheet.Range($rowCounter.ToString() + ":" + $rowCounter.ToString()).NumberFormat = "m/d/yyyy"

$excel.application.DisplayAlerts=$False
$chart = $chartsheet.Shapes.addChart().chart
$chart.hasTitle = $true
$chart.chartTitle.text = "Ramp Example"
$chartType = [Microsoft.Office.Interop.Excel.XlChartType]::xlLine
$chart.chartType = $chartType

$startCell = $datasheet.Cells.Item(3,2).Address($false,$false)
$endCell   = $datasheet.Cells.Item(3,10).Address($false,$false)

$startCell + ", " + $endCell

$datarange = $datasheet.Range($startCell, $endCell)
$chart.SetSourceData($datarange)
$chart.SeriesCollection(1).Name    = "First"
$chart.SeriesCollection(1).XValues = $datasheet.Range("B2", "J2")

$newSeries = $chart.SeriesCollection().NewSeries
$chart.SeriesCollection(2).Values  = $datasheet.Range("B4", "J4")
$chart.SeriesCollection(2).Name    = "Second"
$chart.SeriesCollection(2).XValues = $datasheet.Range("B2", "J2")


$excel.Visible = $True

错误：

用“1”参数调用“SeriesCollection”的异常：“无效参数”在C：\ localwork \ tfs \ OpenExcel.ps1：49 char：24 $ chart.SeriesCollection <<<<（2）.Values = $ datasheet .Range（“B4”，“J4”）CategoryInfo：NotSpecified：（:) []，MethodInvocationException FullyQualifiedErrorId：ComMethodTargetInvocation

用“1”参数调用“SeriesCollection”的异常：“无效参数”在C：\ localwork \ tfs \ OpenExcel.ps1：50 char：24 $ chart.SeriesCollection <<<<（2）.Name =“Second “CategoryInfo：NotSpecified：（:) []，MethodInvocationException FullyQualifiedErrorId：ComMethodTargetInvocation

用“1”参数调用“SeriesCollection”的异常：“无效参数”在C：\ localwork \ tfs \ OpenExcel.ps1：51 char：24 $ chart.SeriesCollection <<<<（2）.XValues = $ datasheet .Range（“B2”，“J2”）CategoryInfo：NotSpecified：（:) []，MethodInvocationException FullyQualifiedErrorId：ComMethodTargetInvocation

问题是; how do I get an extra entry into the SeriesCollection with powershell code?

任何帮助将不胜感激