I dont know on what servers this is working on, but its working on beyond wow.
First, get a enchanting bag, i use Big Bag of Enchantment - Thottbot: World of Warcraft
Then get a Greater essence, i use Greater Nether Essence - Thottbot: World of Warcraft
Then when you are in Sunwell/Silvermoon, equip your enchanting bag in the last slot. In your backpack, Place your Flying mount in the top left corner, and in the enchanting bag, place the Essence in the bottom rigth corner.
Now dubble rigth click the essence and you should start using the mount!
Now you can fly and explore whole sunwell/silvermoon (if you do, link my post xD)
Anyway, i got pics on my comp but dont have time to upload rigth now.
Hope you liked it!