Hello Pit,
You have to contact the Certificate Providing authority ( say verisign ) to get a Trusted Certificate,, Else there is no point in security right ??
Anyone would claim then self as a Trusted Person ...
Else they ( whom so ever is Receiving the content ) should save your certificate in their Browser in the Trusted Certificate Repository ,, so that it wont throw any Alert ..
Regards,
Sheltan T T