S&AS question datatype URI syntax

This is a comment on:
http://www.w3.org/TR/2003/CR-owl-semantics-20030818/
sections 2 and 4.


I had assumed that the following is not legal OWL DL

eg:prop rdf:type owl:DatatypeProperty .
_:a rdf:type owl:Thing .
_:a eg:prop "foo"^^<http://www.example.org/some/uri>.

because the URI used in the typed literal is not a datatypeIDs  (either 
xsd:XXX rdfs:XMLLiteral or maybe a user datatype declared as such - I have 
lost the plot on the resolution of the last possibility).

However I can't see how S&AS rules out the above graph.

Have I misread this, or is it intended, or is it a bug?

Jeremy