VAT on opening balances

When you start using Quickbooks and open a client account it asks for your opening balance. When on cash accounting, the opening balance will include a net sum that has alteady been accounted for in the previous year's accounts income, and an amount for VAT that is to be accounted for once the invoice is paid.

I can't see how Quickbooks is dealing with this - or is there something else to be done when setting up the brought forward balance? It doesn't seem to ask the rate of VAT for this balance either.

Thanks!