How do I customize the Membership Authorize.net receipt description

I'm using Membership plugin and Authorize.net payment gateway.

When the customer receives a receipt from Authorize.net, it doesn't contain the product description, so it's cryptic to the user what the receipt is for.

I spoke to customer service at Authorize.net, and he said that the receipt would include a product description, but that information isn't appearing in the Authorize.net system. Membership is sending the payment amount but not a description.

How do we sent a description to be included on the receipt?