InfoPath Dev

You also will not be able to set File Attachment controls to read only when you are customizing a SharePoint List form. I did come up with a workaround for this using repeating sections and hyperlinks. Full details here: http://vincepangan.com/?p=220

 You could also just push the attachment through the SP file/imaging (if it's an image) web services and keep just the link.
I do this all the time so that the form doesn't contain the attachment it just links to it in another document library (which I think is more appropriate because you can link to it in other forms/webparts later)