Split Deposit between taxable and non-taxable sales?

Split Deposit between taxable and non-taxable sales?

I have a deposit for $1,000.  $900 of this was for non-taxable sales, the rest was for taxable sales. We do our invoicing in another system (not ZB), so we just record the income to an account. How can I split this deposit so my sales tax payment calculation is correct? Or do I need to do an adjustment "generating the tax due"?