Microsoft rsweb:ReportViewer Background

Question

Hello.

I'm attempting to make transparent a ReportViewer on InternetExplorer. It works fine on Firefox but it doesn't on Internet Explorer. It shows a white background. On Firefox it shows the background with an alpha and you can se the background image but on Internet Explorer it doesn't works.

Here is the URL: www.incolmotos-yamaha.com.co/appclientescrm/Admin/puntuacion.aspx

Any advice????

Thanks