Reporting service 2005 , Matrix , Table visibility expression BUG

Reporting service 2005 , Matrix and Table visibility hidden expression  BUG
Issue when design report that contain more than one template (matrix / table)

Example , I create a report that can use only one MDX Query set to generate multiple style of matrix view.
Then i decide to build template parameter  and let user choose what they want to view.
And i set the hidden property (under visibility of matrix) to show or hidden when user selected a template.
Expression : = IIF(template_id=1,FALSE,TRUE)   <------ That's mean user have selected the 1st template.
And this matrix will be show. It' seem to be alright when viewing from web browser .
But when export to excel file , +/- symbol is gone! , Toggle is not working!!! - -"


Why this happen to a basic logic ? I have tested so many case but no luck.And I'm not found solutions to solve this issue yet.


This error not found on SSRS 2008  Y_Y.