HtmlUnit wait for Bootstrap remote modal

Question

I have code for open bootstrap remote modal:

function showModal(url) {
    $('body').append('<div class="modal fade" id="modal" tabindex="-1" role="dialog" aria-hidden="true"><div class="modal-dialog"><div class="modal-content"></div></div></div>');
    var modal = $('#modal');
    modal.on('hidden.bs.modal', function() {
        $(this).remove();
    });
    modal.modal({
        show: true,
        remote: encodeURI(url)
    });
    return modal;
}

This opens remote modal correctly with:

<a id="mdl" onclick="showModal('http://localhost/modal1.php')">Open</a>

modal1.php:

<div>Modal!!!</div>

Now I want to test it in HtmlUnit. So I wrote

WebClient web = new WebClient();
HtmlPage page = (HtmlPage) mWebClient.getPage("http://localhost/");
page = (HtmlPage)((HtmlAnchore)page.getDocumentElement().querySelector("#mdl")).click();

Now the problem is that the content is unreachable.

page.getDocumentElement().querySelector(".modal .modal-content"); // Return object
page.getDocumentElement().querySelector(".modal .modal-content div"); // Return null

Its looks like that the page doesn't get the elements from the AJAX call. (In real browser its works)

I tried:

web.waitForBackgroundJavaScript(100000);
web.waitForBackgroundJavaScriptStartingBefore(10000)
web.setAjaxController(new AjaxController() {
        @Override
        public boolean processSynchron(HtmlPage page, WebRequest request, boolean async) {
            return true;
        }
});

And it still not working...

It is like the $.load function not working in HtmlUnit.

How can I check the content with HtmlUnit?