I'm receiving  the error  message:

"A web  Part or Web Form Control on this Web part  Page cannot be
displayed or imported  because it is not registered  on this site  as
safe."

I tried the procedures  from the SDK. I'm using the wppackager to create  an MSI file.
Things I tried:
- create a custom policy
- modify and added SafeControls, IPermissions, Code Groups

These worked when I tried creating  an MSI package for a third-party web part.
The one I'm working on is for Single SignON.
Do you happen to have some experience in configuring SSO?