this may fix MS voice command
http://www.randyrants.com/2007/05/wm6_tip_voice_c.html
you can find that certificate in Internet Exporer (go to Internet Options, Content, Certificates, Trusted Root Certification Authorities and find the one with that serial number) and export it to a .cer file. copy it to your phone and open it in file explorer to add it to your certificates.