Ok, just autowiring neo4jtemplate i got the createrelationship with the allowduplicates param...
Maybe it would be interesting to have it also in RelationshipOperationsRepository. What do you think?
For those interested:
PropertyContainer originPC = this.neo4jTemplate.getPersistentState( origin );
PropertyContainer targetPC = this.neo4jTemplate.getPersistentState( target );
commentRegistry = this.neo4jTemplate.createRelationshipBetween(
originPC, targetPC, Comments.class, "comments", true
Thanks again... and congrats... again too