The simplest way is to use an orchestration, accept an untyped message (System.Xml.XmlDocument), send this message setting the [b:90e299c346]Microsoft.XLANGs.BaseTypes.Address[/b:90e299c346] property on the send port.
You will need a custom pipeline using the MIME/SMIME encoder and set the [b:90e299c346]BodyAsAttachment[/b:90e299c346] property on this component
If yoiu wish to get more complicated and add a body to the email then I suggest you read the following Biztalk 2004 docs – all the info here is still relavent for Biztalk 2006.
[url]http://msdn.microsoft.com/library/default.asp?url=/library/en-us/sdk/htm/ebiz_prog_email_wgxr.asp[/url]