Dim prefix As String = "sk~"
 
Dim strTempFile As String = IO.Path.GetTempFileName()
 
Dim strtempfilename As String = IO.Path.GetFileNameWithoutExtension(strTempFile)
Dim strtemppath As String = IO.Path.GetDirectoryName(strTempFile)
 
IO.File.Delete(strTempFile)
 
strTempFile = IO.Path.Combine(strtemppath, prefix & strtempfilename & ".pdf")
 
IO.File.Copy("zu kopierendes File", strTempFile, True)