B. Roukema, Z. Bulinski, A. Szaniewska, and N. Gaudin. (2008)cite arxiv:0801.0006Comment: 20 pages, 22 figures, accepted in Astronomy & Astrophysics, software available at http://adjani.astro.umk.pl/GPLdownload/dodec/ and MCMCs at http://adjani.astro.umk.pl/GPLdownload/MCMC.