here is what i did. other pictures are in my gallery.
let me know if you think they are reasonably acceptable.
i used the foam that held the helicopter in the box and shaped it with an exacto blade and sand paper. when i got the shape i wanted, i "painted" them with finishing resin diluted with alcohol. the foam was then painted with fuel proof paint. i also built triangles out of balsa to elevate and tilt the seats.
i built a box that went across the fuselage from window to window. the battery and receiver are under the box. velcro was installed on the box and the triangles. this enabled me to remove the seats for maintenance of the mechanics or repairs.
i have the gi joes zip tied in place, but you can use rtv to make it more realistic.
if i were to keep the heli, i would probably make new seats. i believe the ones in my md500 are too thick.
let me know if you have any other questions.
just do it!