If you want to send a VoiceMail via EWS and have the UM controls appear in Outlook and OWA so it appears the same as it was generated from Exchange UM you need to set a number of different extended properties on an Email Message when you send it. The full list of properties is documented in the following Exchange Protocol document . While some of these properties are optional the most important is to the set the PidTagVoiceMessageAttachmentOrder http://msdn.microsoft.com/en-us/library/ee202885%28v=exchg.80%29.aspx property which needs to be set to the name of the attachment. You also need to make sure you set the ItemClass to IPM.Note.Microsoft.Voicemail.UM.CA . The following is a sample of sending a mp3 voicemail as a message with powershell, I've put a download of this script here . ## Get the Mailbox to Access from the 1st commandline argument $MailboxName = $args  #MessageProperties $VoiceMailSuject = "Voice Mail from .."