(Un)Subscribe in C API?

[dough]

I am trying to subscribe to a UPnP Event when an evented property changes. Following "Eventing Specific Properties" in the ohNet_ControlPointStack guide, I have:

1. Created the proxy.
2. Set a callback for when the property changes.
3. Prepared the callback the get the current state of the property when it executes.
   

The call back is not being triggered, although I can see the event broadcast by my Upnp device by using Device Spy.

The guide suggests that I should be calling Subscribe for the proxy, but I cannot find that API call anywhere in the C API guide. Am I missing the Subscribe step or is it not necessary when using the C API?


...Or perhaps the call back is not occurring for the same reason I cannot get a response from invoking a Upnp action? Can I generate a trace for property eventing?

Doug