SenderEmailAddress property does not contain a standard email address for internal contacts
<p><strong>Background:</strong></p>

<p>Using an Outlook Rule to trigger a script, I want all of my email from certain high-visibility clients to open immediately upon receipt.</p>

<p>I have successfully set up a rule that triggers when those clients send me email. It looks something like this:</p>

<p><a href="https://i.stack.imgur.com/UgIYg.jpg" rel="noreferrer"><img src="https://i.stack.imgur.com/UgIYg.jpg" alt="emails from Jobs and Wozniak"></a></p>

<p>And I have successfully created a script that opens a reply to the email, depending on who sent it. It looks something like this:</p>

<pre><code>Sub OpenEmailImmediately(oEmail As Outlook.MailItem)

    Select Case oEmail.Sender
        Case "Jobs, Steve"
            oEmail.Reply.Display
    End Select

End Sub
</code></pre>

<p>Although this works, I have implemented it using <code>.Sender</code> property. </p>

<p><strong>Problem:</strong></p>

<p>I would <em>prefer</em> to implement this using the sender's email address (a unique value associated with every email I receive). Unfortunately, <code>oEmail.SenderEmailAddress</code>, which I expected to contain the email address, <em>only worked for external clients</em>.</p>

<p>While troubleshooting, I discovered that where I expected <code>oEmail.SenderEmailAddress</code> to have a value similar to this: </p>

<blockquote>
  <p>steve.jobs@apple.com</p>
</blockquote>

<p>for internal emails it had a value similar to this: </p>

<blockquote>
  <p>/O=APPLE/CN=RECIPIENTS/CN=JOBSS6738</p>
</blockquote>

<p><strong>Question:</strong></p>

<p>Is there a way I can make this script work for internals <em>and</em> externals using their standard email address?</p>

<p><strong>Code with implemented solution:</strong></p>

<p>Using Dmitry's answer below, the code was modified to use the email address:</p>

<pre><code>Sub OpenEmailImmediately(oEmail As Outlook.MailItem)

    If oEmail.SenderEmailType = "EX" Then
        Select Case oEmail.Sender.GetExchangeUser().PrimarySmtpAddress
            Case "steve.jobs@apple.com"
                oEmail.Reply.Display
        End Select
    Else
        Select Case oEmail.SenderEmailAddress
            Case "tom.brady@patriots.com"
                oEmail.Reply.Display
        End Select
    End If

End Sub
</code></pre>