My salary details document is not in English.
Can I translate it on my own (including the currency) or should it be some sort of official translation?
Do you have any other related proof in English? For example, a paystub, or a bank statement? Then add them as well.
Yes, I guess a translation should be fine. But I would recommend you to ask this question directly to Tech Nation.
They are quite prompt in answering.
Instead of the translation, you may consider asking for a letter from the Employer written in English specifically for this visa. I think it would look even better and may include employer recommendation as well as financial information.
Disclaimer: I don’t work for Tech Nation and I don’t represent Tech Nation. I am not a lawyer and this is not legal advice.
Tech nation also answered me:
"For the translations, we typically are looking for a certified translation (there are a number of organisations who provide this service) or another method to guarantee the credibility of the translation to our assessors. "