Hi sergejs,
these values are reported everytime, but with a false id:
false statement (at least in actual version 1.4: (.1 at the end)
SNMPv2-MIB::sysContact.1 = STRING: rcmcronny
SNMPv2-MIB::sysName.1 = STRING: MikroTik-250GS
SNMPv2-MIB::sysLocation.1 = STRING: RoomA
correct statement should be: (.0 at the end)
SNMPv2-MIB::sysContact.0 = STRING: rcmcronny
SNMPv2-MIB::sysName.0 = STRING: MikroTik-250GS
SNMPv2-MIB::sysLocation.0 = STRING: RoomA
As there is no .0 ID for these values, cacti or any other snmp solution will not display these informations. (Thats what the Topic starter means 
).
Please have a look at my sum post for bugs and features, if you can give some feedback on these, it would be great
=> Forum-thread: http://forum.mikrotik.com/t/feature-requests-bugs-summary-rb250gs-rb260gs/45095/1
Ronny