Hide columns in table interface

I've used SAP's 'How to ... Hide a column in your Web Query with the Table Interface". The problem is that if I do any OLAP function my headings reappear. It doesn't look like the 'structure_cell' method is being called. Is there a way to force this method to be call? Or is there a flag to reset in the table class that tells the class that this is the first time running the report. It seems that the initinal run is different than if you use any OLAP function.