Integrating the Polymer webcomponent paper-card

Moving from Vaadin 8 to 10, I encountered a problem, which should be rather trivial to solve. When integrating the webcomponent paper-card, I do not see how to add the elements card-actions and card-content as children inside the component’s own DOM element (setting a property etc. is straightforward, see below).
Thanks for any suggestions!

@Tag(“paper-card”)
@HtmlImport(“frontend://bower_components/paper-card/paper-card.html”)
public class PaperCard extends Component{

public PaperCard() {}

public void setHeader(String header) {
this.getElement().setProperty(“heading”, header);
}

Try something like
Element actionChild = new Element(“paper-card-actions”);
getElement().appendChild(actionChild)

Thanks for the reply! The card-actions element still remains invisible in the browser.

Interestingly however, the DOM-tree of the paper-card displayed by Chrome contains the card-actions element, the one displayed by Firefox not.

@Tag(“paper-card”)
@HtmlImport(“frontend://bower_components/paper-card/paper-card.html”)
public class PaperCard extends Component{

public PaperCard() {
	this.getElement().setProperty("heading", "Header");
	this.getElement().setProperty("image", "http://placehold.it/350x150/FFC107/000000");
	
	Element actionChild = new Element("paper-card-actions");
	actionChild.appendChild(new Button("Button").getElement());
	getElement().appendChild(actionChild);

}

}