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Add language node <language code="[language-code]" name="[language name]" /> to the <languages /> node in web.config.
Copy incentive.resx to incentive.[language-code].resx.
Copy RadEditor.Main.resx to RadEditor.Main.[language-code].resx.
Copy RadEditor.Tools.resx to RadEditor.Tools.[language-code].resx.
Add <name lang="[language-code]" text="label text" description="description text" /> to all <setting /> nodes and translate in web/App_Data/settings.xml.