TinyMce not inserting <br />

I'm using TinyMce to insert/edit a text from a database, but I don't know why the <br />'s are missing. There are no new lines, even if I hit ENTER or SHIFT + ENTER.

TinyMce init:

tinyMCE.init({
    mode : "textareas",
    theme : "simple",
    force_p_newlines : false,
    force_br_newlines : true,
    convert_newlines_to_brs : false
});