Update : this is now bug 538021
Since I had a break from my exams (next is on monday), I wrote a little tutorial about writing Anjuta plugins in Vala, it is still incomplete.
I'm posting it here before sending a patch to have more visibility and hopefully someone can proofread it. I'm not really confident about it's quality (and this is the first time I'm writing a software documentation).
Enough speaking, Here you go :