I'm trying to automatically add an attachment to a PDF file through VBA. From what I can tell it is possible to handle this through FileAttachment annotations.

    Dim testAnno As Object
    Dim props As Object
    
    Set testAnno = jso.AddAnnot
    Set props = testAnno.getProps
    props.Type = "FileAttachment"
    
    ' Code to attach file to PDF as attachment ......
    
    testAnno.setProps props
    
  

I've found the following example in the Adobe documentation so essentially looking for a VBA equivalent to this:

var annot = this.addAnnot({
page: 0
type: "FileAttachment",
point: [400,500],
author: "A. C. Robat",
contents: "Call Smith to get help on this paragraph.",
cAttachmentPath: "/d/a.pdf" ,
});