mailto with attachments in Flex or AIR applications

How to forward attachment(for example image) from Flex or AIR application to email client? For forwarding email address, body and subject, I use this:

var s:String = "";    
s+= "mailto:";
s+= g.text;             开发者_如何学编程  
s+= "?";
s+= "subject=" ;
s+= grup.text;
s+= "&";
s+= "body=";
s+= message.text;                                               
var url:URLRequest=new URLRequest(s);       

navigateToURL( url);

But I don't know what to do for attachment.... Please HELP!

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mailto protocol does not support attachments.

http://old.nabble.com/Re%3A-How-to-attach-a-local-file-to-an-email-with--URLRequest-from-AIR-p28091212.html