Adding GST via Paypal's GST calculator.

Hi, I purchased the Protected Content plugin recently under the impression that it supported Australian GST (via Taxamo) but unfortunately it doesn't. I've been looking into some solutions for this and it appears that Paypal have a GST (and shipping) calculator that can be utilised to apply GST to transactions but Protected Content doesn't take advantage of this. I don't understand how it works but Paypal helpdesk said that it looked like the plugin would require a bit of extra code to implement and that I should contact their technical support about it. I have made a ticket with them but you may have better luck having worked with Paypal already. Are you able to help here? Thanks.

Kind regards
Mitchell