WikiPageUtil.addPage(page, PathParser.parse("SomeChild"), "");
WikiPage pageOne = WikiPageUtil.addPage(root, PathParser.parse("PageOne"), ""); //...page must exist!
WikiPageUtil.addPage(pageOne, PathParser.parse("ChildOne"), ""); //...page must exist!
PageData data = page.getData();
WikiPageProperties props = data.getProperties();
WikiPageProperty symProp = props.set(SymbolicPage.PROPERTY_NAME);
symProp.set("InternalAbsPage", ".PageOne.ChildOne");
symProp.set("InternalRelPage", "PageOne.ChildOne");
symProp.set("InternalSubPage", ">SomeChild");
symProp.set("ExternalPage", "file://some/page");
page.commit(data);