aspose-words版本：21.1
java：1.8
tinymc：5.0.16

    public void convertPageBreak() throws Exception
    {
        String sourceHtml = "hello<!-- pagebreak -->world";
        sourceHtml = sourceHtml.replaceAll("<!-- pagebreak -->", "<br style='page-break-before:always'>");
        new Document(new ByteArrayInputStream(sourceHtml.getBytes())).save("output.docx");
    }

tingymce的分页符对应的html源码为：<!-- pagebreak -->