Donation feature does not override the price

-- HikaShop version -- : 3.0.1
-- Joomla version -- : 3.7
-- PHP version -- : 5.6

Hi

Want to make a custom field where a user can put in the value of the voucher he wants to buy (and let it be sent as e-ticket with the support of attach serial plugin).
Example: User puts in "300" for a voucher which should be worth 300 Euros.

I activated the donation plugin, created a custom field of the table "item" with the column name "amount".
Like it is in the demo.

The field is there, but when adding to the product to the cart ....the value of the custom field does not override the price.
(no difference if there is a price for the product or not / "free")
No overwriting at all.

What did I miss?

Hi

I tried with all 3 possible settings in the plugin - same result, no overriding of the price.
-No taxes
-On top of the amount
-already included in the amount

Screenshot:

Hi,
thank you, this should have been obvious.

Another questions:

- Can I restrict the field to digits (123...0)?

- How could I prescribe a minimum (user shall fill in more than for example 100)? Is this possible?


thanks
Walter