How to create double sided meshes in OBJ export ?

Hello,

Excuse-me if this this question was already asked in this forum, but I didn’t find it with the search engine.

I use Blender to create 3D objects at OBJ format, then use them in Sweet Home 3D a free interior design application I developed.
Even if the “Double Sided” button in Mesh panel is checked, I never get double sided meshes in the OBJ file. What should I do ?

Note that I would prefer not to duplicate objects and flip their normals. :wink:

Thank you for your help.