We are a financial services organisation and do not want to offer credit card payments as a matter of course, but would occasionally frind it useful to offer it at our discretion for small value transactions.particularly as we deal with a number of elderly people who do not use the internet or have an online bank account.
So my suggestion is to have the means to set up the system so the "pay online" button does not appear on any invoice but there is the option when adding the payment against the invoice that one of the options of registering the payment is card payment, so in isolated instances under our control we can collect an individual payment by credit card