Unable to use it in noconflict

[cortopy]

I'm trying to run this plugin like many others I use in no conflict mode

However, running this code in my usual way gives errors and plugin doesn't work at all.

$j = jQuery.noConflict();
$j(document).ready(function(){
    $j('form').idealforms({ 
        field: '.field',
        error: '.error',
        iconHtml: false,
        invalidClass: 'invalid',
        validClass: 'valid',
        silentLoad: true,
    });
});    

I'm a bit lost as to why this method doesn't work. I've tried changing the $ sign in the .js file but with no success either