To enable PDT:
Click the My Account tab. Click the Profile sub-tab. Click the Website Payment Preferences link. The Website Payment Preferences page opens. Click the Payment Data Transfer radio button to ON.
You must enable Auto Return in order to use Payment Data Transfer. Auto Return can also be enabled from the Website Payment Preferences page.
Set the Return URL: 'https://your privatelabel install/exec/sgnpaypal' Click Save.
When you click Save and save your PDT preferences, a message appears at the top of the page indicating that you have successfully saved your preferences. Your identity token also appears in this message.
For security, the identity token is not sent to you; however, once you have enabled PDT, it permanently appears below the Payment Data Transfer On/Off radio buttons on the Website Payments Preferences page.
PayPal has such feature as a sales tax. It allows you to set tax on certain transactions. By default all Diamondcard transactions will be taxed according your PayPal settings. You may override them from Diamondcard admin center at:
PE->options->payment methods->PayPal