Better late than never:
1. Confirm that your ia6b is bound to the actual used model on FS-i6 sender. You should see the current voltage of the receiver in the display of the sender..
2. Got to i6-Config-Menue and confirm that PPM is set off for the receiver of this model. The ia6b supports PPM (one signal) and PWM (many signals).
3. The channels of I6 are 1 for pitch, 2 for roll, 3 for throttle and 4 is yaw in mode2, you can check that in i6-main-menue. main-port of cc3d is not the same order, check your wires.
With that done, the wizard should get your input.
It is faster and more reliable to connect the ia6b to the flexiport of the cc3d. With GCS config first tab, you can set disable+oneshot for mainport and set flexiport to ppm. Set ppm on i6 config-menue for your model. The Wizard will not recognize this configuration, you must set the channels manual on config-input-tab of GCS. Select the right channels and ppm for pitch, roll, yaw, throttle and flightmode-switch. Use manual calibration to set the endpoints. Do this without props!
Hope that helps.