Hello,
Yes, that was the right move but the translation is made in the "preload" part, not in the email.
Because translation can have parameters, these can't be within the HTML email template.
So, if you need to change another translation in an email, please look at the preload for more detail 
Regards,
Jerome - Obsidev.com
HikaMarket & HikaSerial developer / HikaShop core dev team.
Also helping the HikaShop support team when having some time or couldn't sleep.
By the way, do not send me private message, use the "contact us" form instead.