You will find that at some point you need to be a little more clever with sending mail than what InfoPath will allow you to do with just the GUI and dataconnections. A colleague of mine, Scott Heim, sent me an awesome little XSN file that had 4 buttons in it that highlighting four different ways to kick off e-mail programmatically from InfoPath. If you e-mail me I'll send you the file. The code however is pretty easy to follow and is posted here for your enjoyment.
XDocument.UI.ShowMailItem "firstname.lastname@example.org", "", "", "Subject: Test", "Body: Test"
End Sub '
Set oEnvelope = Application.ActiveWindow.MailEnvelope
oEnvelope.Subject = "Subject: Test"
oEnvelope.To = email@example.com
oEnvelope.Visible = true
'Create the Outlook session.
Set objOutlook = CreateObject("Outlook.Application")
Set objOutlookMsg = objOutlook.CreateItem(0) 'olMailItem
'Add the To recipient(s) to the message.
Set objOutlookRecip = .Recipients.Add(firstname.lastname@example.org)
objOutlookRecip.Type = 1 'olTo '
'Add the CC recipient(s) to the message.
' Set objOutlookRecip = .Recipients.Add(email@example.com)
' objOutlookRecip.Type = 2 'olCC '
' 'Add the BCC recipient(s) to the message.
' Set objOutlookRecip = .Recipients.Add(firstname.lastname@example.org)
' objOutlookRecip.Type = 3 'olBCC
'Set the Subject, Body, and Importance of the message.
.Subject = "This is an Automation test with Microsoft Outlook"
.body = "This is the body of the message"
' **NOTE: if you want the body of the message to be HTML, then use '.HTMLbody instead of just .body
.Importance = 2 'High importance
'Resolve each Recipient's name.
For Each objOutlookRecip In .Recipients
'Display the message before sending
'If you want to add the form as an attachment, you need to make sure it is saved first and then add that file as an attachment
'** NOTE: THIS REQUIRES THE FORM TO BE FULLY TRUSTED!!!
frmSavePath = "C:\MyForm.XML"
Set objOutlookAttach = .Attachments.Add(frmSavePath)
Set objOutlook = Nothing
Set objOutlookMsg = Nothing
Set objOutlookRecip = Nothing
Set objOutlookAttach = Nothing