As of now there is not an option to do that. You could edit the plugin code directly if you wanted to get that done, but that’s not typically recommended. If you’re a developer you could also extend the plugin with a child class and override our function so you can build that PayPal request however you want to.
I have added this request to our issue list on our GitHub repo. I’ve got it added to the 1.2 milestone, but it may be a couple of months before that’s ready. Sorry I don’t have better immediate news.
If you would like some help getting that working the way you want on your site in the mean-time you could submit an order for premium support and we could get that done for you.
I’m going to mark this as resolved for now, but let me know if you have any other questions.
