I have correctly configured ActiveSync certificate-based authentication, however, when I tested it on my iPhone mobile device, I encountered these error logs on the server (server exchange 2010) :
2010-08-12 23:51:36 ip_address POST /PowerShell serializationLevel=Full;clientApplication=EMC;ExchClientVer=14.1.218.6;PSVersion=2.0 80 CONTOSO\Administrator ip_address Microsoft+WinRM+Client 500 0 0 179996
2010-08-12 23:53:39 ip_address POST /PowerShell clientApplication=EMC;ExchClientVer=14.1.218.6;PSVersion=2.0 80 CONTOSO\Administrator ip_address Microsoft+WinRM+Client 500 0 0 179998
2010-08-12 23:54:30 ip_address POST /powershell serializationLevel=Full;ExchClientVer=14.1.218.6;PSVersion=2.0 80 CONTOSO\Administrator ip_address Microsoft+WinRM+Client 500 0 0 179994
2010-08-12 23:54:36 ip_address POST /PowerShell serializationLevel=Full;clientApplication=EMC;ExchClientVer=14.1.218.6;PSVersion=2.0 80 CONTOSO\Administrator ip_address Microsoft+WinRM+Client 500 0 0 179996
2010-08-12 23:56:39 ip_address POST /PowerShell clientApplication=EMC;ExchClientVer=14.1.218.6;PSVersion=2.0 80 CONTOSO\Administrator ip_address Microsoft+WinRM+Client 500 0 0 179996