All applications - GTK+ and KDE(Qt4) look the same - fonts smaller than 12pt are not antialiased and fonts bigger tahn 12pt are antialiased, only for U++ applications all font sizes are antialiased (with my current settings). And this is under KDE, LXDE and Openbox.
When using Gnome or XFCE4 U++ applications look like the oter applications it seems that there is something running (like gnome-settings-daemon) which fixses it.
and now U++ applications look like the other applications under all desctop enviroments I've tryed.
It looks that when gtk_antialias = -1; gtk uses the default settings of X server.
I also uncomented row 674 and comented row 675:
674 gtk_hintstyle = GtkStyleString("gtk-xft-hintstyle");
675// gtk_hintstyle = gtk_hinting? "hintfull" : "hintnone"; // Gtk does not seem to follow its own rules...
and it works fine - before there where or full hinting or no hinting, now slight and medium hinting also work.