Put the following in the superclass for your components:

  private String anchor;
  
  public void appendToResponse(WOResponse response, WOContext context) {
     if (anchor != null) {
        response.setHeader(context.componentActionURL() + "#" + anchor, "location");
        response.setHeader("text/html", "content-type");
        response.setHeader("0", "content-length");
        response.setStatus(302);
        anchor = null;
     } else {
        super.appendToResponse(response, context);
     }
   } // appendToResponse

   public String getAnchor() {
       return anchor;
   }
 
   public void setAnchor(String s) {
       anchor = s;
   }

In the component where we want to use an anchor you just put in

 <a name="myanchor"></a>

and something like the following in the code where we want to jump to this anchor:

  protected WOComponent doSometingAndJumpToAnchor() {
     // do something :)
     setAnchor("myanchor");
     return null;
 }