Invoice Email API with PDF attachment

I need to email invoices directly to our customers using the API.  The invoice emails sent from AccountRight have both a PDF attachment and a Pay Now link (https://paydirect.myob.com/pay/#/<Guid>?source=email-view&type=invoice).

Using the Item Invoice Email endpoint I can email the invoice, but with no PDF attachment.

Using the Render As PDF endpoint I can get the PDF and attach it to an email, but then I cannot find a way to create the Pay Now link.

Is there a way to solve either of these two problems so that an email can be sent using the API with both the PDF and Pay Now link?