Hi @thomas_stuempfi,
We have no immediate plans to support SPARQL in neosemantics unfortunately. Essentially because we have Cypher that covers the need for a structured graph query language. Is cypher not an option for you?
If you don't want to export the data as RDF and import it into Jena, the only option I can think of is the development of a SPARQL endpoint as an extension to Neo4j. Is that a project you'd be willing to undertake? If that's the case I'd love to hear about it.
If not, maybe you can share a bit more about what you're trying to achieve and maybe we can find some workaround?
Cheers,
JB.