Airport Design Editor and SDK's

I just installed Airport Design Editor, in hopes of making my home airport closer to the real thing. However, after I installed and ran ADE, it gave me a new user wizard. I followed the steps, until it told me it needs paths to work properly. I clicked find, but it only found FSX, no SDK's. I read that you need the deluxe version of FSX to get the SDK's. Is this true? If it is, is there any other possible way to get the SDK's? Because if I can't get the SDK's, then I'll have to live with no hangars, incorrectly placed fuel pump, taxiway markings wrong, and several other incorrect things. 
