Probably I was too upset to express myself clearly, but you got the point (or maybe my lacks in english show up).
When coming out of the printer the sheet looked fine, but when I applied it on the model the color was too transparent to be seen.
Trigger74
Alps makes printers that can print white and metallic colors. So I hope to get opaque colors. I've contacted the company and I'm awaiting a reply. Here's a link:
http://members.xoom.virgilio.it/huey/alpsdecals_gb.html
HeavyArty
It sound like a good idea to run them through the printer more than once but you risk streaking the color from the first pass. Should you try, please let me know if it worked.