I find that if credit card is under the same name as passenger, they never ask. But if credit card pays for someone elses's flight, they usually do ask question.

What you can do is just take a photo-copy of credit card, and have someone in company sign a waiver form acknowledging that it's a legitimate purchase. CX afterall just wants to be able to cover themselves, so this will get your way through. It doesn't need to be laywer's masterpiece, just a simple A4 form saying you are entitled to have fee charged to the credit card you used.