Complete tax return when no longer living in Belgium

Hi,
I left Belgium (de-registered and surrendered my ID card) in January this year.

Now I have to complete my tax return for last year, bit I have no way to login to the tax-on-web without an ID card. I read about getting a token to login, and have emailing them, but they tell me the only way to obtain a token is to go in person to one of the local tax offices, which simply isn't possible for me now since I live in another country and don't have time to go back to Belgium just for this...

Has anyone else been in this situation and how did you manage to do it? I'm willing to complete my tax returns...if only I knew how!

Thanks for any advice.