Comment by ehamberg

I simply tried (and failed, it seems) to say that they are generally considered to be equivalent, and that it's okay to use “aa” when translating a name with “å”. Reasons for this could be not knowing how to write an ‘å’ (or Ł, đ, ç, ì, etc.) or simply not wanting to distract one's readers. I do not have an authoritative source.