I've not been able to find a shape match to the vase so far, and also it seems that all the Poschinger vases have a firepolished rim - but there is one that appears to have a cut and polished rim in the Passau museum (it's on the left hand side at the back of one of the larger group displays in the photos below -c an't remember what page sorry).
But if your vase were mine I would still be leaning to Harrach at the moment.
I've attached a link to Poschinger displays in the Passau here - if you click forwards there are about 5 or 6 pages (pages 73-77) of Poschinger so you can compare. They are pretty amazing glass

so worth a look anyway.
Mod: Link removed as content changed to inappropriate sitem