如何通过EWS和PowerShell向Exchange导入含参会者的ICS日程

我正尝试将包含参会者的约会/会议导入Exchange，遇到了不少困难。现有示例大多针对无参会者的约会，但我需要从ICS/MIMEContent文件导入含参会者的日程。我参考了微软官方的EWS导入导出文档，尝试了如下代码片段：

$enc = [System.Text.Encoding]::UTF8 
$mimeBytes = $enc.GetBytes($mime)
#$mime here is the mimecontent file, loaded in as a string.

$mimeContent = New-Object Microsoft.Exchange.WebServices.Data.MimeContent 
$mimeContent.CharacterSet = "UTF8" #also tried 'UTF-8' and a few other things
$mimeContent.Content = $mimeBytes

#$ExchangeService is my service connection to EWS
#$impersonateAddress is the meeting recipient email address 
$ExchangeService.ImpersonatedUserId = New-Object Microsoft.Exchange.WebServices.Data.ImpersonatedUserId([Microsoft.Exchange.WebServices.Data.ConnectingIdType]::SmtpAddress, $impersonateAddress)

$ImpersonatedFolder = New-Object Microsoft.Exchange.WebServices.Data.FolderID([Microsoft.Exchange.WebServices.Data.WellKnownFolderName]::Calendar, $impersonateAddress)

$Appointment = New-Object Microsoft.Exchange.WebServices.Data.Appointment($ExchangeService) 
$Appointment.MimeContent = $mimeContent

$Appointment.Save($ImpersonatedFolder)
#also tried:
#$Appointment.Save([Microsoft.Exchange.Webservices.Data.SendInvitationsMode]::SendToNone)
#$Appointment.Save($ImpersonatedFolder, [Microsoft.Exchange.Webservices.Data.SendInvitationsMode]::SendToNone)

我知道多数指南不建议导入含参会者的约会，因为涉及参会者副本关联，但肯定有可行的方法！所用ICS文件是标准格式，已提前加载为字符串并转换为字节。

内容的提问来源于stack exchange，提问作者BM100