I'm here to guide you on how to track and claim your zero-rated product that contains a commission with 20% VAT in QuickBooks Online.
To record the product that you sell and its commission in QuickBooks Online, you'll need to add a second line item specific for the haulage charge. This way, you can add the 20% VAT on the transaction.
However, in doing this, you may contact our Customer Care Team so they'll be able to do the process for you. They have the tools to be used in adding a VAT only charge in the system.
You may also check out these resources attached below to give you more details about adding a product and service transactions and the different VAT rates in QBO: