Difficult integral

I have encountered an integral that i cannot solve.
The integral is
int_0^{k_f} int_0^{k_f} log(|k-q|/(k+q)) kq dk dq
(see <http://www.zaim.dk/integral.jpg> )
it should give -1/2*k_f^4.

I have tried this: Split the inner integral up in integrals over [0;q] and [q;k_f], in order to get rid of the numerical sign. I used partial integration, but I just get some new integrals which I cannot solve.
Any ideas on how to progress?

Anders
.