how to attach a file to OUTLOOK.APPLICATION object

[amigo02]

I have following code and works fine

var outlookApp = new ActiveXObject("Outlook.Application");
var nameSpace = outlookApp.getNameSpace("MAPI");
mailFolder = nameSpace.getDefaultFolder(6);
mailItem = mailFolder.Items.add('IPM.Note.FormA');
mailItem.Subject="CUSTOMER SERVICE";
mailItem.To = document.frmM.txtEmail.value;
mailItem.HTMLBody = objXMLHTTP.responseText;
mailItem.display (0);

but I would like to send the html as an attachment instead of using "mailItem.HTMLBody = objXMLHTTP.responseText"

Any idea how to do it