Hi Fran.
If you go in to your user cp along the top of the forum bar, there is a window down the left side, then there is an edit options icon silver wheel icon, click this and scroll down to interface message options, there is an option that allows you to activate and add attachments there, hope ive explained it ok, if not a more experienced member could elaborate on this.
Dave.

PS, i found out through another member, as i did not know.