I'm pretty sure there isn't a method to get the active configuration with the EPDM API. You'll need to use the DocMgr API.
There is not a direct method via the EPDM API but there is a way of acheiving it, unfortunately though it requries the hook to be one of the Card types. For example the EdmCmdType.EdmCmd_CardInput provides the name of the active configuration via the mbsStrData1 member. You can then use this as a paramter to the GetConfigurations Method.
As i say unfortunately i do not think this will help you with a stand alone application but thought it was worth sharing this information.
I had noticed that too, which is why I was hoping I had overlooked the call to get this info. I assume that EPDM stores this info somewhere and doesn't actually call the document manager every time it needs to know the active configuration.
Unfortunately that info is only passed as info in a hook, so that doesn't really help in standalone situations - as you pointed out.