"Does the skin editor never show the textured model ? my model is always white."

It always shows the textured model - I don't even know how to make him to show it not.

Is your tga 24bit or 32bit?
First means it is without alpha channel, means there is no 'in-build' transparancy.
Second has an alpha channel where the black parts are completely invisible while the white parts are in-transparent, and all other parts are more or less transparant depending the values of there grey.