we've got an external, woo-commerce based gift card system in which we issue and redeem gift cards. if a customer pays both with a gift card and a credit card, is there any way to correctly account for it in netsuite? we're using cash sales (which might be the problem) so the payment's being allocated to the item lines... but ideally we'd have one transaction to register the gift card amount, and one to register the remaining cc amount

A cash sale is Netsuite's way to wrap the Invoice & Payment into a single transaction based on assumptions it will be consistent. In your case, you want to 'apply' two different payment methods which will need an Invoice. You just need to work out your own automation of the external gift card (which is probably unique to you.)

thanks!