Ok here is a link to them available commercially..
FORD Aerostar Alloy Wheels - Replacement and stock OEM @ WheelsAndCaps.com
You can see a picture there without the center caps on...
and let me see if I can get a picture up with center caps...
Oh here is an image of the center caps... as commercially available..
1995 Ford Aerostar OEM Center CAP - Wheels / Rims, Mirrors & Lights Store
note.. the center caps have a small nub that are fake lug nuts.. I believe I have seen ones that are flat without the fake lug nuts.. but mine have the fake lug nuts on them.