I've configured IPs for MGMT-ports of all my Exteme switches and connected them to dedicated 2960. Ping works fine but I am unable to connect to the switches with SSH or telnet.
So there is a policy file called mgt.pol. That probably prevent you of logging in.
With "vi mgt.pol" you can see the content.
with "configure telnet access-profile none" you can remove the access profile.