Ok so it is the trade stations within the same gravitywell which stack? Sounds cool and more important possible 
. What is your issue, they simple doesn't stack, minidumps, did you use the dev.exe and got some specific error? You could upload the files so we can have a look at them if you don't have anything specific errors or such (please mark the abilities and press on the insert code block, so it is more readable, just chose one of the languages, doesn't matter much)
