Bootstrapped mic FET (Internally biased), how to bias?

[ELS122]

I have a circuit that bootstraps the crappy fet inside an electret mic. But the problem is that those fets have internal diode leakage junctions tied to the source, internally.
And thus I'm having difficulty figuring out a way to bias the circuit.
My current design works ok but it's very susceptible to temperature or transistor changes.