Add Subject Line to Email Hyperlink

I'm trying to script the application of a hyperlink to email from a character style. I've managed to make it work for the most part but now I'm at a loss about how to modify the Subject Line in the hyperlink that is created. Any ideas?

var myDoc = app.activeDocument;  
app.findGrepPreferences = app.changeGrepPreferences = null;  
  
app.findGrepPreferences.findWhat = ".+";  
app.findGrepPreferences.appliedCharacterStyle = "Email Hyperlink";  
var myFound1 = myDoc.findGrep();  
  
count = 0  
for(k=0; k<myFound1.length; k++)  
{  
try{  
    var myFind = myFound1;  
    var myHyperlinkSource = app.activeDocument.hyperlinkTextSources.add(myFound1);  
    var myHyperlinkURLDestination = app.activeDocument.hyperlinkURLDestinations.add("mailto:"+myFound1.contents);
    var myHyperlink = app.activeDocument.hyperlinks.add(myHyperlinkSource, myHyperlinkURLDestination, {name: myFound1.contents+count++});  
    count++  
}catch(e){}  
}  
  
alert(count/2 + " E-Mail Hyperlinks Created");