How can I use an espresso maker on an induction cooktop?
It sounds like the only thing you can do is use an interface disk - basically a piece of metal that is compatible with the induction cooktop, which will then transfer the heat to the espresso maker.

You can also potentially use an induction-compatible pan as an interface - see this question.

Unfortunately either way, you'll lose the fast-response benefit of the induction cooktop, because you'll now have to wait for the interface to heat.