Mustang has a JAAS login module that supports authentication at an LDAP Directory
(com.sun.security.auth.module.LdapLoginModule). Upon successful authentication
the login module creates a javax.security.auth.x500.X500Principal object.

Occassionally, although authentication has completed successfully at the
Directory, the login module throws an exception. This is caused by restrictions
imposed by the X500Principal class. Customers are becoming increasingly frustrated
with this limitation.

The X500Principal class represents a security principal identified by an X.500
distinguished name. It supports both the binary ASN.1 DER encoding of
distinguished names and the string encoding defined in RFC 2253. However, not
every string distinguished name can be transformed into its binary encoding.
Because of this, the X500Principal class must reject a small class of valid
string distinguished names.