I can't enable it when Russian Federation selected. When selected US - all work fine.
Hmm. Those parameters all come directly out of the wireless drivers — if it's not shown, it's probably either because the wireless driver thinks it's not permitted in Russia, or because there's some other parameter that's incompatible with 40 MHz mode that is being forced to change when switching to/away from US.
802.11n in Russia
Currently, the standard has officially certified. Equipment for the 802.11n standard has been approved for use in the territory of Russia in the band 2400-2483.5, 5150-5350 and 5650-5725 MHz Order of the Ministry of Communications of Russia from September 14, 2010 № 124 "On approval of rules of radio equipment. Part I. Regulation of radio equipment for wireless transmission of data in a range from 30 MHz to 66 GHz. Preparation of standards for application of the standard involved FSUE Research Institute of Radio (NIIR).
Do you really expect the Broadcom wireless driver made in 2008 to know about September 14, 2010 order of the Russian' Ministry ;)?
Anyway, if the driver doesn't allow you to select 40MHz for Russia, just configure it to use some other country.