Thank you for your commment, deba_avik and Captain Qorax!
I have no intention at all to play around with CIC or VO. I just want to make clear that, rather than filling "Your intended occupation" with sth relating to 4131, which I'm pretty sure is impractical (due to language barrier, credentials recognition, regulated occupation, jpb prospect, etc... I've done some research, of course), should I fill in my real (and quite practical) plan? I have no docs, experience etc to match my intention now, but I'm intending to take training from start in a complete different field which I know is within my own resources and capability. "Honesty is the best policy", right?
After all, I'm not sure about the purpose behind this "Your intended occupation" in form IMM0008. What on earth VO has to do with our plan after landing? Do they probably evaluate our case by this "Your intended occupation" or not?
Good lucks !