Tradeskill Combine for Enchanted Velium Powder is not Working
 

This is the first step on the 7th shawl quest:

Head off to Siren's Grotto and kill Sirens until you get a Runed Sea Shell with one charge of Enduring Breath.

Combine the Sea Shell and a small brick of velium in a Mortar and Pestle (if you are a rogue) or in a Mixing Bowl (any class) to get an Enchanted Velium Powder (No-Fail Combine).

When I attempt this combine in the mixing bowl it tells me that i cannot combine these items in this container type.

http://i.imgur.com/b7lJj2R.jpg

So i have figured this out.

apparently you MUST use the mortar and pestle (rogue) for this combine and the mixing bowl simply does not work.