I encountered the same thing on NWA.com, but was able to get it fixed immediately when I called the elite line. This was for an "I" ticket.

I had purchased an international "B" fare partially funded by an ECV and upgraded with miles on nwa.com. I got the same message that it would be applied, but the receipt didn't reflect this.

I called the elite line the same day, and they explained that the website computers just were not able to process both at the same time. This had to be done manually, and it took them a bit to figure it out.

Ultimately I was able to use the ECV toward the B fare, and miles to upgrade. My original full B-fare was refunded. It took about 2 months before they deducted my miles, but I have always been listed as WBC. I look forward to the trip to visit my brother and family in Japan in the fall.

I was platinum at the time, and this likely contributed toward the "fix" going very smoothly for me. I did have both the full "B" fare and the B fare minus the ECV on my credit card for a while. I got the original fare refunded on the next billing cycle, but if you don't have the cash flow to cover it, it could be a problem.

I would recommend that people who want to pay for an ECV and then use miles to upgrade go ahead and call first. Hopefully the regular reservationists would be able to help as well, although I am not looking forward to eventually having to test this out. I will miss the elite line when I am no longer gold.

NWA.com and the computer processes were the barriers here, not the ECV itself.