Looking a tutorial to make a custom part!

[Simone]

Your LDraw code is a bit wrong, since it uses a part with front face  and overlaps a front face with texmapped pattern. Attached a more correct version.
...but I doubt this is the source of your problem.
LDview renders front face as opaque:

and LDCad renders the pattern as transparent:

Also with your code i'm still getting the same behavior.
I thought I got the same result that you got with ldview. Where could I have gone wrong? Do I need to enable a particular setting on the LDview render engine?