How does one upgrade a Subtle Essence into a Shimmering Essence? [duplicate]

Possible Duplicate:
Is it possible to “upgrade” the crafting materials?

My question is as it reads in the title, how do you upgrade the Normal-mode crafting Essence (Subtle) into the Nightmare crafting Essence (Shimmering)?

There are hints on various wikis and forum posts stating that the Subtle Essences can be re-crafted or reforged into Shimmering Essences...but no direct answer as to how I should go about it. I would assume there is a special blacksmithing recipe that you either purchase or acquire from Haedrig in order to craft it but again, I have found nothing of that sort thus far.

To clarify: I know that item levels 1-30 drop Subtle Essences after salvaging, and I know that item levels 31-50 drop Shimmering Essences after salvaging. What I am interested in converting Subtle Essences into Shimmering Essences. Is it even possible, or is this notion outdated (left over from the beta)? Just an incorrect assumption?

You can't.

Any subtle essence's you have will have to be used or sold, as there is currently no way to "upgrade" them.

There may have been in the past (I'm not sure how true this is) but if so, it was removed before release.

Update for Patch 1.0.5

As of patch 1.0.5 it is now possible to upgrade essences (as well as tomes of training) at the Blacksmith at a ratio of 10:1.

More information can be found in the official post for this patch

According to Blizzard's own site, there is no method to upgrade Essences. If you take a look at the Subtle Essence page, you will see there is no mention at all of being able to upgrade it; I don't know where the Diablo Wiki site got that info, but it's wrong.

To my knowledge, there is no way to upgrade ANY item, beyond inserting gems. You can salvage items, and use that salvage to create new items, but there's no way to directly turn gear into another piece of gear.