Is it possible to single step onto an agent's voice mail call. I attempt to single step twice and nothing happens. What is the expected behavior?

At one level a call is a call, and you can single step into a call. At another there are various feature and environmental restrictions that can prevent SSC from entering a particular call or all calls at a particular device.

Can you SSC at all (station to station)?

For 'nothing' to happen is rare. Did you check the DMCC Trace? Enable TSAPI tracing? ASAI via MST? Denial Events? any, some or all may have an indication of why the request wasnt acted on.

Have you checked the COR restrictions (probably on the trunk to VoiceMail) to see if one is preventing the SSC? Was exclusion active? Were there adequate VoIP resources when the request was made? This list is quite lengthy.. I would start with the logs and work from there.

ok thx