To create translations for extensions you must make sure you are using the x18n operator instead of the i18n. The x18n operator is similar to i18n but takes the extension name as the first parameter, ie.
{"Name"|x18n('myextension','design/standard')} Then create the translation file with lupdate and place it in extension/yourextension/translations.
Maybe it's a bug of ezlupdate (windows version) or something else:
If you write something like {"Okay"|x18n('mymodule', 'design/standard')}
the translation file will be "corrupted", in the ts-file following entry is produced:
<name>'design/standard')}"</name> (instead of <name>design/standard</name>)
So don't make a whitespace between 'mymodule' and 'design/standard'.