How can i downgrade my ipod touch 3G 3.1.3 to 3.1.2?

Also i've downloaded 8.0 and 8.2 and neither of these let me do the whole "Shift and click on restore thing" so i'm pretty annoyed i would like to jailbreak it so i can have an emulator on it, not to steal things. I've downloaded the 3.1.2 and 3.1.1 off multiple sites and they all have completely ruined my day, if anyone has a few links they can send me, i would really appreciate it, or if someone has the next jailbreak release date i would appreciate it very much. and are the rumors true about blackr1an waiting until the 4.0 firmware??