GraphDB custom ruleset for inference over RDF* statements

I am trying to add a simple rule to the builtin RDFSPlus (Optimized) ruleset to be able to have GraphDB generate inferred (implicit) statements from RDF* assertions.

Specifically, referring to GraphDB example here https://graphdb.ontotext.com/documentation/9.4/free/devhub/rdf-sparql-star.html, starting from these assertions:

    :hasSpouse a owl:ObjectProperty ,
                 owl:SymmetricProperty .

    :man :hasSpouse :woman .

    <<:man :hasSpouse :woman>> :startDate "2020-02-11"^^xsd:date .

I would like to have the GraphDB reasoning engine to infer these two statements:

    :woman :hasSpouse :man .
    <<:woman :hasSpouse :man>> :startDate "2020-02-11"^^xsd:date .

No problem for GraphDB to generate the first one (obviously), but the RDF* one is proving a little tricky.

First I tried to add this rule to a copy of the builtin RDFSPlus (Optimized):

    Id: owl_rdfstarOverSym

      a b c
      b <rdf:type> <owl:SymmetricProperty>
      <<a b c>> p q
    ------------------------------------
      <<c b a>> p q

In this case I was not able to create the repository; GraphDB console showed this exception:

    Error in rule 'owl_rdfstarOverSym'. Invalid identifier: '>'

I then tried to add the rule with only one '<' and '>', like this:

    Id: owl_rdfstarOverSym

      a b c
      b <rdf:type> <owl:SymmetricProperty>
      <a b c> p q
    ------------------------------------
      <c b a> p q

GraphDB seemed to be able to create the repository, however trying to use SPARQL results in this error message: 'Failed initializing inferencer', and the GraphDB console shows this exception:

    Invalid entity: 'c b a'

All these tests were run with GraphDB free edition: Version: 9.3, revision: 41892658

Thanks in advance,

Franco

As Damyan Ognyanov stated in his comment (GraphDB custom ruleset for inference over RDF* statements), what I was trying to do is not possible with GraphDB rule language.