To be sure I understand correctly, you mean that if one redeems a Fixed Flight award Expedia will generate a charge for the taxes and fees and this will post to your credit card as a flight transaction? .
I don't have a Chairman card, but I do have the Premier Pass. Last summer, I booked 2 flights of award travel, and paid for a third ticket. I put the fees/taxes on my PP credit card, along with my paid ticket. A couple months later, all 3 flights showed up on my statement, but all three had zero miles. I'm tried to get credit for at least the fully paid ticket, but Citibank insists that I fax the documentation to a fax number that rings and never picks up.
I'm wondering if it just looks at the dollar amount of the transaction compared to the mileage, and makes a determination that way. Still, even that doesn't explain why I didn't get credit for the third ticket.