The WCF Configuration Editor doesn't show-up in the right-click menu for WCF Service Host app.config files when the project wasn't created using a WCF project template. You can, however, wire it up given a quick trick. From the Tools menu choose WCF SvcConfigEditor and immediately close the editor. Until you close the project the WCF Configuration Editor context menu will now be available when right-clicking the app.config.
Why? By design? Dunno...
Follow-up
By design? Yup. Why? VS startup performance. Found this Indigo Forum post after initially publishing.