No code but principles.
So rc-servos don't give a feedback, you give a setpoint to the servo and has to wait a time so it is finish moving (typically rc-servos can turn 60°/s).
Then start ranging and read SRF08 til you don't get 0xFF anymore (ranging is finish).
Than you can read the echo register 1-17 (register 2-35), til a 16 bit register (8-bit high-byte and 8-bit low-byte) is 0, what means no further echos for this reading stored.
That is the principle of one measure cycle.
Description and example code you can find here: