I did the same thing a couple of days ago. I faxed the information to a wonderful helpful HH assistor and she told me it would post in 24 hours or so, but it might not hit the hotel's reservation system for 3-4 days, and that the card might take 2 weeks.

I watched my account and by the end of the day she had input all of the information and I was Diamond.... really happy with the whole process.