export class OverlayComponent {
  embeddedViewRef: EmbeddedViewRef<any>;
  @ViewChild('mntPageOverlayContainer', {read: ViewContainerRef}) container: ViewContainerRef;

  showTemplate(value: TemplateRef<any>, props?: OverlayProps) {
    this.embeddedViewRef = this.container.createEmbeddedView(value);

    if (props && props.onShow) {
      this.embeddedViewRef.rootNodes.forEach(element => [make modifications to it]);
    }
  }

<ng-container #mntPageOverlayContainer>
</ng-container>