[Membership 2 Pro] Paypal single gateway: Include customer country in invoice

Hey there,
We're currently developing an external service to automate our invoice generation. Based in Germany, we serve customers from both within and outside of the EU. A piece of legislation passed back in 2015 directs us to disclose the VAT separately for each invoice, giving rise to the necessity of retrieving our customer's residence country. While to our knowledge this information is sent as part of the paypal IPN, one cannot retrieve this information within an action call outside the membership plugin. Hence, we would like to submit this as a feature request to be included in the invoice as an additional and accessible attribute.
As a workaround, we use the customer's IP to associate a buyer country, which is error prone in some edge cases (e.g. the customer is at an airport traveling back to her/his home country etc.)