How can I access to AK8975 via MPU6050 I2C aux master

I am using the MPU6050 EVK and I am trying to access to AK8975 via the aux i2c master.

with the following instructions I try to read the AK8975 id code:

write 0x20 on the reg USER_CTRL (set I2C_MST_EN)
write 0x08 on the reg I2C_MST_CTRL
write 0x0E on the reg I2C_SLV0_ADDR (i2c addr of AK8975)
write 0x00 on the reg I2C_SLV0_REG (AK8975_RA_WIA)

Now on the reg EXT_SENS_DATA_00 I should read the value 0x48
but I always read the value 0x00

do I wrong something?

thanks