Run the "SP_AllowCertificateInstall.cab" file attached
Use the registry editor "regeditSTG2" attached to change
HKEY_LOCAL_MACHINE\Security\Policies\Policies (then press "values")\ 00001001 = 2 -->Change the value data from 2 to 1
HKEY_LOCAL_MACHINE\Security\Policies\Policies0001005 = 16 --> Change the value data from 16 to 40
HKEY_LOCAL_MACHINE\Security\Policies\Policies0001017 = 128 --> Change the value data from 128 to 144
The following reg editors DONT work
A possible alternative could be to run the "SP_AllowCertificateInstall.cab"
And then the HTC application unlocker attached (which for me didnt work before I ran "SP_AllowCertificateInstall.cab" but does work after I've run "SP_AllowCertificateInstall.cab")
To ensure your phone is fully unlocked, run SDA_ApplicationUnlock on your PC (it is not meant to be run from Windows Mobile).
Make sure you re-boot your device before running SDA_ApplicationUnlock