Installing snow leopard on mountain lion using vmware fusion 6

I have just purchased my mac book pro but I need to use some software that require Rosetta. I am installing snow leopard on mountain lion using vmware fusion 6. I have a dmg file for snow leopard. All the software are legit. I have gone through some threads in the forum but they did not work for me. I have tried converting my snow leopard dmg file to iso and put in vmware but it does not work. It boots at first but later shows an icon (circle and line on it) and is stuck. Can anybody tell me detail steps for installation?