keyIdentifier valuetypes of Username and X509 profiles are definedrelative to wsse schema

In its table 2 (beginning on line 177), the X509 profile defined token
value types using URI fragment identifiers, relative to the URI for the
containing specification (i.e the X509 profile).

This approach ensures that the token value types include the version of
the profile in their full URI.

Conversely, the x509 token profile requires that  a KeyIdentifier ValueType
be specified and that it carry a core relative URI (i.e. 
wsse:X509SubjectKeyIdentifier)

One of our goals was to be able to version profiles independent of the 
core.
The choice of the core relative URI does not preclude independent profile
versioning, it just complicates the recognition of the token profile version
in the case of the profile version 1 X509 keyIdentifiers, since the version
of the wsse schema must be interpretted to imply the version of the profile.

The next version of the X509 profile could acheive independent versioning
of keyIdentifier valueType by requiring the use of a profile relative 
fragment
identifier for keyIdentifier ValueType.

The USerName token profile prohibits the use of keyIdentifier's.
However in its table beginning on line 242, and in contrast to the 
requirements
of the X509 profile, it requires that (when specified) that token value 
type
(in a direct reference) be specified using a core relative URI fragment 
identifier (i.e. wsse:UsernameToken)

The next version of the USername token profile could acheive independent
versioning of token valueType by defining a profile relative fragment
identifier for Reference value type.

To allow for simple and consistent core independent identification of 
token profile
and version, both of the discussed used of value types (in all of the 
profiles) should
be profile relative.

Ron