in an effort to comply with the requirements for add-on publishers, I am happy to officially introduce my small hack addon:
IC2 Extra Fuels
Quoting the github description:
This mod is an Industrial Craft 2 addon that allows free configuration of additional fuels to be consumed by Industrial Craft's Semifluid Generator.
The mod is especially intended to be used by users of Buildcraft until the new set of fuels introduced in Buildcraft 7.99a (Dense Fuel, Gaseous Fuel, etc.) are officially supported by Industrial Craft. See this bug report.
I hope someone finds this useful.
Also, "proper" default values for dense fuel, gaseous fuel and "normal" fuel (and additional fuels) are more than welcome. I'm still figuring them out myself.