The Poser 8 figures and Miki4 use the encapsulated joint rigging that was introduced in P8 and then replaced with weight mapping in P9.  If you are having trouble adjusting the joints, you might want to send a copy of the conversion to PhilC.  You can site mail him here or email him at PhilC.net.  He is always willing to take a look at a conversion and help you fix it.