Add Product Custom properties to json that is sent when the "Order Submission" webhook is triggered

Summary:

Hello,

We have a custom product field called "external_Id" this field helps us identify the product in another system that is in charge of processing the order. The problem we have is that when the webhook "Order Submission" is triggered, the json that is generated does not contain the custom field of the product "external_Id" so it is difficult for us to identify the product in the other system. We would like to know if there is a way to add the product's custom field "external_Id" to the json that is sent when the "Order Submission" webhook is triggered.