Failing to set a 3rd party signature handler in Adobe Acrobat 9 Professional Extended

Hi All,
 
I have got a 3rd party digital signature creating plug-in i.e. MySign . I have set it inside 'Preference > Security > Advanced Preferences > Creation > Default Method to Use when Signing and Encrypting Documents' > MySign. If I restart Adobe Acrobat that setting is lost and the Adobe Default Security handler is shown.
 
I don't want my clients to set this handler manually so I have figured out that Adobe Acrobat is creating a registry entry named aPrivKey against that inside cHandlers BUT it gets removed on Adobe restart if I set MySign as handler in the first place.
 
Similarly I want the same handler to verify signatures. For that I have set 'Preferences > Security > Advanced Preferences > Verification > Always use the default method (overrides the document-specified method)' along with the name of handler i.e MySign but on restart of Adobe this is also gets reset.
 
Any idea how to set my handler as default to sign & verify?
 
Regards,
Wahaj