CallbackInfo setting with personalizeUrlWidget request?

Hello - I have created a widget I want to use with multiple customers, and am using the widget's url in a personalizeUrlWidget request, and it's working great. I'd like to add a callbackInfo block to allow the ADC system to ping our system once the agreement has been signed.

Is there a way to do this from within the personalizeUrlWidget request? I see the availability to add the callbackInfo when I create the widget, but I don't want to create a new widget with a unique callback url and then have to personalize the widget after that.

I've tried a personalizeUrlWidget request with the following structure, but it's not working as i'd expect :

[apiKey] => /api key

[senderInfo] => / sender's email

[widgetUrl] => / my widget's url

[personalizationInfo] => Array

        (

            [email] => / signer's email

        )

[

[widgetCreationInfo] => Array

        (

            [callbackInfo] => Array

                (

                    [signedDocumentUrl] => / unique callback url

                )

        )