How to Customize theme code for MYTHEME theme. It is only necessary if you want to create another one like MYTHEME theme. Here are the instructions of creating Custom Theme with MYTHEME standard. How to: Customize Themes You can add new themes or customize existing ones for application to Web sites in Microsoft Windows SharePoint Services 3.0. This programming task shows how to customize an existing theme. To create and customize from an existing theme Copy one of the theme folders in Local_Drive:\Program ......