Model loaded, some invisible faces

Hi buddies,

I have a problem  :?

I’m loading an OJB with JME.

It loads ok, with model and texture. But every first face (facing to camera) of the model becomes invisible.

I suposed that I’m having a trouble with Blender, but I can’t solve it.  :( Any tip?

I Uploaded this screenshots to explain better the problem:

In first one is how it should look like. (You can see outside of box)

In second one is how it looks. (You see inside the box, but trough mesh.)

Both pics are rendered from same perspectives.

Updated info

Are you missing a Z-Buffer state in your scene or maybe the normals weren't correct when you exported from blender.

Thank you Core-Dump