Ionic Animation API Change

recently ionic change the nav animation customization and now i'm not able to change the default slide effect to a normal fade:

.fade.ng-enter {
-webkit-transition-property: opacity;
-moz-transition-property: opacity;
-o-transition-property: opacity;
transition-property: opacity;
-webkit-transition-duration: 0.5s;
-moz-transition-duration: 0.5s;
-o-transition-duration: 0.5s;
transition-duration: 0.5s;
position: absolute;
top: 0px;
left: 0px;
opacity: 0;
}
.slide.ng-enter-active {
    opacity: 1;
}

.fade.ng-leave {
    -webkit-transition-property: opacity;
    -moz-transition-property: opacity;
    -o-transition-property: opacity;
    transition-property: opacity;
    -webkit-transition-duration: 0.5s;
    -moz-transition-duration: 0.5s;
    -o-transition-duration: 0.5s;
    transition-duration: 0.5s;
    position: absolute;
    top: 0px;
    left: 0px;
    opacity: 1;
}
.fade.ng-leave-active {
    opacity: 0;
}

Then i added this to my nav:

<ion-nav-view class="fade"></ion-nav-view>

This not worked for me so i tried to change the config with $ionicConfigProvider.views.transition with no result. I only obtained that the animation disappare and now there are no effect.

Someone can point me to some documentation? Thanks.