ezlupdate cannot determine all possible values of the variable you set as input for i18n here. But the translation should work if you manually insert all possible values of the variable (meaning the names of all your attributes) into the translation.ts yourself.
So if the name is 'foo' which you want to translate to 'bar', add the respective info to your translation.ts in the context you have specified. As the translation.ts is an xml file you can open it in any txt editor (be careful to keep the utf8 encoding if necessary). You can see that the structure is quite easy to understand.
Please note that the ezlupdate will choke on variables as input for i18n so you might have to comment out the respective template line, run ezlupdate and then comment the line in again. Afterwards add the additional translations as required.
