install new library, here Qwt

[thom]

Hello,
Some time ago that I had managed to install the library qwt on windows but now I've tried stuff and I can not do it ....
Here are the steps I have made ​​watching the doc of qwt and searching on the forum:

1) Unzip in qwt -> C: \ Qt \ qwt-6.0.0
2) open the control box of Qt -> QT 4.7.3 for desckop (MinGW)
3) execute -> qmake qwt.pro
4) execute -> mingw32-make
5) execute -> mingw32-make install
6) execute -> qmake-set QMAKEFEATURES "C :/ Qt/qwt-6.0.0/features"
7 °) added -> "CONFIG + = qwt" in my. Pro
8 °) in Qt once I go into the menu -> Compile and then -> "execute Qmake"
9 °) and then I compile my project

I am doing this but it still does not work, when I compile Qt tells me that is not "Qwt_curve.h" which
is a function of the library qwt I use: P

I'd like to understand what art what it lacks in the installation process, I feel that everything is good ...
apparently may need to be doing other weird things but I do not know when the installation procedure and how ... :

10 °) to add something in the. Pro​​?
10 °) to add something in the. Pri? (where is this file, there are several non?)
10 °) to add something in the. Prf? (this is the file that is here?: C :/ QtSDK/qwt6-0-0/features)

Thank you for the help you can give me I'm really in trouble: (

thank you very much

A +