Prova con questo script:
codice:
<%
Sub ReplaceInBodyPart(bp)
Const strTokentoFind = "SIGNATURE"
Const strTokenToReplace = "Benny WONG Chee Khiun"
Set objStream = bp.GetDecodedContentStream
strContent = objStream.ReadText
strContent = Replace(strContent, strTokentoFind, strTokenToReplace)
objStream.Position = 0
objStream.SetEOS
objStream.WriteText strContent
objStream.Flush
Set objStream = nothing
End Sub
Sub modifyHtmlAndTextBodyParts(msg)
Set objBP = msg.HTMLBodyPart
ReplaceInBodyPart objBP
Set objBP = nothing
Set objBP = msg.TextBodyPart
ReplaceInBodyPart objBP
Set objBP = nothing
End Sub
Set objMsg = Server.CreateObject ("CDO.Message")
With objMsg
.To = """TUONOME"" <tuo_indirizzo@email.it>"
.From = """Nome_Mittente"" <aaaaaaaa@aaaaaaaaaaaa.it>"
.Subject = "This is the subject"
.CreateMHTMLBody "http://www.google.it"
End With
ModifyHtmlAndTextBodyParts objMsg
objMsg.Send
Set objMsg = nothing
%>
Se ti serve puoi renderla dinamica.

Ops, scusa questo script usa CDOSYS, comunque puoi modificarlo