fuel neck and door

Hey whats up. i am bodydropping my s-10 bed and smoothing the inside with sheet metal and i have a problem, i want to shave my gas door but i dont know what to do with the neck i would like it on the inside i've seen some but dont really know how they have them hookd up any pics or ideas would be appreciated i would post pics but dont know how. want to do fuel cell just not right now, want to do it later when i redo frame work. thanks for suggestions and pics.