'securityDomain' elements are decoded to ProfileElementSD instances, which keep higher level representations of the key data apart from the decoded[] lists.
So far, apply_val() was dropping binary values in decoded[], which does not work, because ProfileElementSD._pre_encode() overwrites self.decoded[] from the higher level representation.
Implement using - ProfileElementSD.find_key() and SecurityDomainKeyComponent to modify an exsiting entry, or - ProfileElementSD.add_key() to create a new entry.
Before this patch, SdKey parameters seemed to patch PES successfully, but their modifications did not end up in the encoded DER.
(BTW, this does not fix any other errors that may still be present in the various SdKey subclasses, patches coming up.)
