Typotheque Webfont Service supports all characters that our fonts support. Look up the particular font that you are interested in, and see all Glyphs that it support. For example, Fedra Sans Book supports over 2500 glyphs.
When creating webfont project in your account, select which languages you would like to support. You can choose as many languages as you like. Should you want to support just a specific glyph, enter it in the Custom field, so you are sure it is embedded in the webfont.