Hello,
In the LiveIntegration v2 (I've checked the source code for 2.3.0 beta 4), the object ProductInfo is not populated will all the fields that come from the ERP response, there are just some hardcoded properties (e.g. ProductId, TotalPrice, Stock etc) and the custom fields on products if the "AddProductFieldsToRequest" is set. You can check this in the ProductManager class in the ProcessResponse(XmlDocument response) method.
It means that right now the only way to populate it with some custom data that our ERP partners are sending back to us is to define for all of them custom fields on the products, and to set the "AddProductFieldsToRequest" to true in the settings. This has the downside that we are polluting the products with fields that are used only for communicating with the live integration and are not stored on products, and if we have a lot of custom fields, all of these will be sent to the ERP when making the requests.
Regards,
Emil