custom field to substract an amount

Hi,
I am not able to make my custom field work, which is set to substract an amount to the total.
This is what I wrote on Values:

Sí, estoy suscrito a RevistaMAITRI.es (tus datos serán comprobados para validación) (-4.65€)
No, no estoy suscrito/a a RevistaMaitri.es por ahora (-0€)

And on Fee Values:
4.65
0

And I think is should be fine, but at checkout, it adds 4.65 instead of substracting the amount. I am using a radio list therefore I didn't write anything on the fee formula box.

What could be going wrong here?


(Also, I would like to point out that the screenshot used on the tutorial ( joomdonation.com/index.php?option=com_co...icle&id=80&Itemid=72 ) has Fee Field set to no, it might be helpful if set to yes, I remember getting confused by this... in case it can help others.

Thanks.

As replied via support ticket, to substract an amount, you need to add a minus ("-") character before amount. For example, in this case, you need to change fee values to :

-4.65
0

After that, it should work as expected !

Tuan