Windows Mobile 5 email encryption and digital signature

[Lutz]

Hi,
I'm testing the email encryption and digital signature functionality
on Windows Mobile 5 (OS 5.1.195 Build 14955.2.3.0).
My personal certificate is imported via p12import and it shows up in
the certificate store. So I can encrypt messages but cannot decrypt
messages nor sign messages. So I believe something is wrong with the
private key. I have also configured the email encryption in Active
Sync on my mobile. My cert is for all purposes.
Cheers
Lutz