Hello Mauricio, First of all, sorry for the delate on answering but i have been busy and out of all this stuff and forum for some time. Thanks for your words and interest in my models. I appreciate it very much. I don´t have a special technique, i do have a special patience. If you can specify a little more i can explain you the special detail that you want. In which part of the window do you see the special thech? I use the 11 x-acto knife with a brand new blade every 10-20 windows and i fix the transparent acetate in the interior, as the aircraft has interior they have another "skin" and the acetate goes between the two skins like a sandwich.