Ok, great. So that file I’m assuming is saved locally, or returned as a string?
If it’s the former, you can do something like this:
/** Get the contents of the file */
$file = file_get_contents("../path/to/file.pdf");
If it’s in a string already, then no need to do this as that step would load the file into a string for you. From there, you encode the string using Base64:
/** Take the file string and encode it using Base64 */
$data = base64_encode($file); `
When it comes to compiling the XML, you set the value of EmbeddedFileBinaryObject to the new base64 string.
I hope that helps?