The machines can use RF.
The recipes is Iron Blocks arranged in the way you would normally craft the furnace.
Hurray, they can use RF...allow me to clarify my point: Since the machines from forestry are almost entirely for bees or trees, which you can't get, the only other use they might have is their engines, which no machine worth using accepts MJ. You can argue mechanism machines can accept it, but why on earth would you do that when their generators are a heck of a lot more efficient?
In any case, I'll give that recipe a go. If it does work, for some reason NEI isn't displaying it. Weird...
Edit: Just tried your suggested recipe, still doesn't work, and I am using your hotfix file for recipes.