Add script to signed tab of digital signature field

I have a script to generate an email when a document is signed.

The script is manually placed in the signed tab of the digital signature properties field.

Under "This script executes when field is signed"

I will be creating a batch script to add the field to the document

I have not been able to find the correct trigger to add the email script to the signed tab for the digital signature properties.

Can anyone please advise the correct trigger name?

Batch script as follows:

var f = this.addField("mySignature", "signature",0,

{120, 85,300, 105]);

f.setAction(?, "this.mailDoc({bUI: false, cTo: "", cSubject:"Document for issue", cMsg: "Document ready for issue,});

Any assistance most appreciated.