Encontrei uma macro do Word para ativar essa funcionalidade no HowTo-Outlook.com, em " Enviar documento do Word como e-mail ":
Sub SendDocAsMail()
Dim oOutlookApp As Outlook.Application
Dim oItem As Outlook.MailItem
On Error Resume Next
'Start Outlook if it isn't running
Set oOutlookApp = GetObject(, "Outlook.Application")
If Err <> 0 Then
Set oOutlookApp = CreateObject("Outlook.Application")
End If
'Create a new message
Set oItem = oOutlookApp.CreateItem(olMailItem)
'Allow the user to write a short intro and put it at the top of the body
Dim msgIntro As String
msgIntro = InputBox("Write a short intro to put above your default " & _
"signature and current document." & vbCrLf & vbCrLf & _
"Press Cancel to create the mail without intro and " & _
"signature.", "Intro")
'Copy the open document
Selection.WholeStory
Selection.Copy
Selection.End = True
'Set the WordEditor
Dim objInsp As Outlook.Inspector
Dim wdEditor As Word.Document
Set objInsp = oItem.GetInspector
Set wdEditor = objInsp.WordEditor
'Write the intro if specified
Dim i As Integer
If msgIntro = IsNothing Then
i = 1
'Comment the next line to leave your default signature below the document
wdEditor.Content.Delete
Else
'Write the intro above the signature
wdEditor.Characters(1).InsertBefore (msgIntro)
i = wdEditor.Characters.Count
wdEditor.Characters(i).InlineShapes.AddHorizontalLineStandard
wdEditor.Characters(i + 1).InsertParagraph
i = i + 2
End If
'Place the current document under the intro and signature
wdEditor.Characters(i).PasteAndFormat (wdFormatOriginalFormatting)
'Display the message
oItem.Display
'Clean up
Set oItem = Nothing
Set oOutlookApp = Nothing
Set objInsp = Nothing
Set wdEditor = Nothing
End Sub
Se você precisar de ajuda passo-a-passo para obter a macro no Word, o link real (acima) terá isso, incluindo imagens.