The way you deal with transactions and postings can vary dependent on how you are set up. The below is an example of a way you could deal with this scenario. If you are unsure this works for you, please check with your accountants, alternatively, please raise a new case online and reference the title of this article.
Post a Client Payment (CDR) - Clearing down the matter ledger client account balance (Client Postings - General Postings).
Post a Bank Receipt (BR) to credit a firm nominal, i.e. your credit card account (Nominal Ledger - Bank Payments and Receipts).
The above 2 postings would need a physical movement transfer from office to client at your bank.
Then post a Bank Payment (BP) which is you Credit Card posting paying the charity, and this could debit the firm nominal, i.e. your credit card account (Nominal Ledger - Bank Payments and Receipts).