well currently it is hard to find anyone who willing to do this.. so here are my suggestion to resolve this issue.
1. make every challenge dungeon drop essence as reward, so it will become the major source of crafting essence. or just simply allow people to exchange material from challenge for crafting essence.
2. planar shard or something similar could be drop in challenge, which can be use to trade various of item such as spirit cake, sp/hp potion..etc