Explicit RDF property for "literal has datatype D"?

Dear all,

  we are working on embedding RDF-based ontologies into another host language
(see below for background).  While saying that some RDF literal has a datatype
is hard-coded into the syntax of any RDF serialization, we would have to make
it explicit in our representation, and our representation of that would
actually be quite close to RDF triples.

Let me say it in terms of RDFS: There are classes rdfs:Literal and
rdfs:Datatype, and what I'm looking for is just a simple property

p a rdf:Property ;
  rdfs:domain rdfs:Literal ;
  rdfs:range rdfs:Datatype .

I could invent p myself, but maybe there is already some established ontology
that contains such a property p.  Do you know any?

Background, for those interested: We are working on improving the
documentation of ontologies.  As a means for that, we use the mathematical
markup language OMDoc, which supports literate-programming-like embedding of
documentation into formalized knowledge.  See
https://svn.omdoc.org/repos/omdoc/trunk/doc/blue/foaf and then
* eswc09-poster.pdf (poster abstract)
* eswc09-a0poster.pdf (poster)
* mkm09.pdf (full paper, but for a more mathematical audience)

Cheers, and thanks in advance, 

Christoph

-- 
Christoph Lange, Jacobs Univ. Bremen, http://kwarc.info/clange, Skype duke4701