Hyper-V replication with certificate !!

Hi Everybody , 

    I have two servers Hyper-A and Hyper-B , but those two server are not in the same domain , but I want Guest-A on Hyper-A replicate to Hyper-B . 

   So , on the configuration , I select "Use certificate base" , but it failed !!! 

   I want to google and search on Microsoft site , I can not get the answer , if anyone colud give some guide to let me can finished this job , thanks !