Adding $60 Full Liter of Juice to KS - How can I do this?

[Anuvin]

And to be clear, that means to edit your current pledge, NOT RE-PLEDGE. Editing allows you to pledge for the printer, and purchase addons. At the end of the Kickstarter, a survey will be emailed to you. The survey will be your opportunity to tell the Peachy folks exactly what you want. Remember to add the cost of shipping.

EXAMPLE -
I have the $100 Peachy Printer pledge. That pledge is $120 after shipping to the US.
I want to purchase 1 liter of resin. It costs $60, and $10 for shipping.
I go to the Peachy kickstarter page. I click "Manage my Pledge". I edit my pledge to the total of $120+$60+$10 for a total of $190.