Don't of know if there's something that allows you to play bass drum and hi hat simultaneously with one foot?
What do you mean by 'play' the hi-hat?
The hi-hat foot control simply opens the hi-hats.
You could put a trigger on the bass drum and have it trigger a hihat sample.
If you want to open the hi-hat every time you hit the bass drum then I have no real idea, other than using a remote hat control and positioning it next to the bass drum.
Would still be a cludge.
I'm struggling to think of a situation where this would be musically useful.
Would you mind explaining the wider purpose of the question?
I might be able to think of a solution for you.
Double bass pedal with your slave pedal next to/ against to the hi hat pedal. Foot in the middle plays both simultaneous.