I don't like either of the answers above so I'm going to add one of my own.
The AH system is not like AW.
You can not just change the skins on your FE. You have to change them in the terrain when you design it.
Skins are terrain specific.
Example, if you change all the skins in the Baltic Terrain, then anyone who flys in the Baltic Terrain (after their machine is updated) would see the new skins.
Additionaly, the AW skins are arranged different in their bitmap pallet. You could use a graphics editor to move and adjust to make them work.
Welcome to the TE!
Viper