mailto function (attachments)

I am busy whith a web application(asp) where the helpdesk operator have to mail the customer’s document to him.
Everything is working, the email program opens, the “To:” address, the “Subject:”, and the “Body:” is there, except for the attached pdf file. Here is the code, can any one please tell me how to fix this problem
?subject=Investment Portfolio-<%=rs("date0")%>&body=A copy of your Investment Portfolio, as requested&insert file=c:\..\OnlineDemo\aims.pdf”>