Word on here is that faxes go straight in the trash. If you go to
disneyworld.com, look for your resort and look at the Overview page for your resort, you will see that they no longer list a fax number.
You can call 407-W-DISNEY and give them your request.
Then call back a few days later and have them read it back to you, to make sure it was entered correctly.
Some people pay to get a subscription at
TouringPlans.com which can put in a room request for you.