If you paid electronically the voucher is not required. From the Hawaii instructions:
Use Form N-200V to send your payment to the Department of Taxation when you are paying a balance due on Form N-11, N-15, or N-310, but you are not making the payment with your return. For example, if you filed electronically, but are not paying electronically, use Form N-200V to send your payment to the Department of Taxation.
