Not sure how to label it, I only know of the ore dictionary.

While crafting the steam hammer I noticed it can only be crafted with immersive steel and not steel from other mods.

Will this be changed in the future or an option added to allow use of other mod material?

The recipe will be going away and be replaced with making a immersive engineering style multiblock

Nice, will that multi-block accept steel from other mods?

Will be fixed by #157