Issue with error message if a pdf form is not signed.

Hi

I have an issue with an error message that I set up on a pdf form. 

If you digitally sign the form by clicking in the Signature field you can sign with a digital signature set up in Adobe, and you can submit the form.

If you don't click the Signature field and sign with a digital signature you can't submit the form and will receive an error message, which is the way it is supposed to work.

However, the problem I have is if someone use the E-Sign area of the form to place a scanned copy of their signature over the top of the Signature field, the javascript does not recognise that the form is signed and you can't submit the form. Is there a way for the following javascript to be improved so that it recognises an E-Signature as well as a digital one?

var Addr1 = "compliance@fairholme.qld.edu.au"
var cSubLine = this.getField("Text1") + " - " + this.getField("Name")
var cBody = "Dear Compliance Adviser, Please find attached my " + this.getField ("Text1") + " for my DocMan file."

if(this.getField("Signature").value.length == 0)
{
app.alert("You must digitally sign this form before submitting.");
}
else
{
this.mailDoc({bUI: true, cTo: Addr1, cSubject: cSubLine, cMsg: cBody});
}

I have attached a copy of the form so you know what I am trying to do.