Before you customize Mail, you need to decide your customization goals. There are several common customization scenarios.
To customize the skin, you need to understand the structure of the underlying Cascading Style Sheet (CSS). The skin color, font style, or font size can be globally changed in the CSS file.
Since the mail client supports internationalization, most of the text used in mail are referenced through a special array named i18n. The strings are saved in <uwc-deploy-path>/webmail/en/i18n.js. To replace the text with a desired text, you need to look up the string from <uwc-deploy-path>/webmail/en/i18n.js and modify it. The default encoding for all files is UTF-8, and you need to ensure that you use the right one, especially when the text contains non-Latin characters.
Mail supports customization specific to each domain. A user who belongs to a specific domain will be directed to a different view (skin) on signing in. Refer to chapter Chapter 8, Customizing Domains for more information on customizing mail for domain.
All Image files are stored in <uwc-deployed-path>/webmail/imx. You can look up the image file name from HTML files and replace the URL with the required one.
To add extra features, you can create a new function using the listFrameHTML() function in the corresponding _fs_lr.jsp You can also add new functions to be called by listFrameHTML(). The new content will then be inserted in the mail application. If the extra feature involves more technical aspects that are not documented, contact Sun Professional Services for assistance.