Create a bulk of test email in Exchange mailbox using Outlook. Specify number of messages to create and a file attachment.

Set objFSO = CreateObject("Scripting.FileSystemObject")

amount = InputBox("Enter No. of mail messages to generate","No. of mail messages",10)

attach = InputBox("Enter the full path of the attachment","Attachment","c:attach.doc")
willAttach = 1

While objFSO.FileExists(attach) = 0
    attach = InputBox("Enter the full path of the attachment","Attachment","c:attach.doc")
If attach = "" Then
  willAttach = 0
  WScript.Quit 
End If   
Wend

Set oOutlook = CreateObject("Outlook.Application")
Set oNameSpace = oOutlook.GetNamespace("MAPI")

For i=0 To amount

Set newMail = oOutlook.CreateItem(olMailItem)
newMail.Subject = "TestMail " & i
newMail.Body = "This is a test mail message generated by VBScript"
newMail.To = "SomeUser"
Set atts = newMail.Attachments
If willAttach Then
atts.Add(attach)
End If
newMail.Save

Set newMail = Nothing
Set atts = Nothing

Next

WScript.Echo "Complete"