Is there any way to get rid of the + sign displayed on edit shipment for the shipping costs?

Thing is, we don't charge for shipping, but we want to grand a discount to people who pickup their parcel.
It all works well, the rate is negative, but it now shows + and - and that has proven to be confusing for people.
Having the sign and symbol the other way around in my currency is not an option, because the display is way better on the cart and invoice like it is.

So basic question: Where is the + symbol put in (that's the one I try to get rid off)? Can't find it anywhere!!!
(also why is it there, you can format your positive numbers in the currency anyway?)

  • Set up a payment method using the Standard plugin.
  • Enter Payment Name as COD or Cash on Delivery and if you charge a fee for this service enter that amount under "Fee per transaction".

It will then be offered as a payment method at checkout.

No need to enter anything else on the plugin.

  • You may wish to edit the confirmation of order email sent to the client.