[Rdfapi-php-interest] Running non-graph queries on a dataset

Hi,

I'm trying to use RAP dataset API (v 0.95) with DB persistence, but I
can't see how to make 'non-graph' queries.

I created my dataset using:

$dbstore = ModelFactory::getDbStore();
$dbstore->createTables('MySQL');
$dataset1=& $dbstore->getDatasetDb('Dataset1');

And then parsed some RDF files to add quads in it - BTW, is there a
way to add quads in the dataset by simply giving a graphURI and a
fileURI ?

Then I used
$dataset1->sparqlQuery($query);

to run queries, but while GRAPH queries return something, I have, for
simple spo queries:

<sparql xmlns="http://www.w3.org/2005/sparql-results#"><head/><boolean/></sparql>

Did I missed something with datasets / queries ?

Thanks

Alex.