Use of blender Import and Export Scripts:
This Tutorial is base on Blender 2.48, and this version is probably mandatory.
Scripts will be updated followind blender versions.
Export window will look like this:
Here is options usage:
SaveAllObjects?:
Set: Will save all scene objects, independently of selected state of the objects.
UnSet?: Only selected objects will be saved. If no object is selected, all objects are saved.