RB2011 is wireless (driver) only, while cAP AX is wifi-qcom (driver) only.
If you want to manage the cAP AX from the RB2011, you need to upgrade the latter to 7.13.x (or above, current stable is 7.16.2).
Then you need to run both the old CAPsMAN (for wireless) and the new CAPsMAN (for wifi-qcom, which can be found in the wifi menu) on the RB2011. This will give you both /interface/capsman and /interface/wifi/capsman
For more info:
http://forum.mikrotik.com/t/7-13-wireless-package-split-question/172049/1