Node Payments module's payment form display options not functioning correctly

The "As a menu tab" and "Amount only with link to payment form" payment form display options made available by the Node Payments module do not work correctly.

After selecting "As a menu tab" in the Payment settings when adding or editing a content type, adding a payment form to a node created using that content type results in no display of the form at all on the final node.

After selecting "Amount only with link to payment form" in the Payment settings when adding or editing a content type, adding a payment form to a node created using that content type results in a display at the bottom of the node of the labels for the values in the donation form's "Recommended amounts" field. No link to the form is included. See attached screenshot for display example.

Drupal version 6.20
Donate version 6.x-1.0-alpha2