powerConnect 6248 + spanning tree + oID(SNMP)

Hello, Could you please tell me how can I show port status on this type of switch (powerConnect 6248). I use 1.3.6.1.2.1.17.2.15.3.x where X is number of port. This oID show me status on ports (1, 2 , 5 ...) Where 2 is important for me. It says port is blocked (because I have got on it spanning tree) There is no problem when I use it on the switch 5448. But on the 6248 switch there is problem Its look like the switch dont know about this oID. I am able only show if the port is Admin down/up or Operative down/up, but no if the port is blocked via spanning tree. Thx you for help.