I think i solved the problem:
I changed the html2element code in the composer-view.js to:
html2element: function(html) {
var $template, attributes = {},
template = html;
$template = $(template(this.model.toJSON()).trim()), _.each($template.get(0).attributes, function(attr) {
attributes[attr.name] = attr.value
}), this.$el.attr(attributes).html($template.html()), this.setContent(), this.renderContent()
},
