Cannot set or read LNA

I have a XB8-DMUS-002
and want to turn on the LNA via the LB command.
Unfortunately the response frame(api enabled) returns a 0x2 = Invalid command.

In the manual -XBee®SX 868RF ModuleUser Guide- the command should be ok, there is no remark for other module variants with no LNA.

It is the wrong module for enabling LNA?