Need help with dinking glass (transparancy/export)

Hi there !
I’m trying to make drinking glass since days and I have trouble with the transparancy when exporting.
I can’t find any tutorial for this, I imported a cocktail from the game to see how it works, it helped me a bit but I still can’t figure out how to solve this problem.

In Blender it looks really fine
image
But when I export and look in CodeWalker it’s ugly
image

Anyone can help me for this ?
Thanks