You can attach the source or message as an attachment using the qie.sendEmail command.
Here is an example code on how to send the source as an attachment:
var attachmentMap = qie.newEmailAttachmentMap();
qie.addEmailAttachment(attachmentMap, 'file.name', source.getBytes());
qie.sendEmail('email@host.com', 'test attachment', 'here is the attachment', attachmentMap);
Sample sending the current message:
var attachmentMap = qie.newEmailAttachmentMap();
qie.addEmailAttachment(attachmentMap, 'file.name', message.getBytes());
qie.sendEmail('email@host.com', 'test attachment', 'here is the attachment', attachmentMap);