My Net WiFi Range Extender - want to limit devices to connect with 802.11n only

Just set up my Range Extender, and things seem to work well.
My firmware version, 1.02.01, is up-to-date.

The Range Extender web interface (Advanced Settings, Wireless, Wireless / Wireless Setup screen) reports:

Network Mode Mixed 802.11 b+g+n
Channel Width 20/40 MHz(Auto)
Channel 2.452 GHz - CH 9

I want to set network mode to “n only”. (I do not want any b or g devices to be able to connect to my Range Extender.)

Is there a way to do that?

Note - The router that the Range Extender connects to is already set to “n only”.

Hello,

According to page #30 of your User’s manual, it is possible to change to 802.11n only

 According to page #30 of your User’s manual

Nah, that refers to AP mode. I am in Range Extender Mode.