To what you have said, I see no other alternative than use the winapi. However, you are clearly much more knowledgeable than I. Here's the situation. You know you have a new device and Windows has enumerated it and given it a COMn. Were you to open MAX and refresh, yes, it would be there, but that's it. That's all you have.
Ever tried to run Find VISA Resources with a search term of "ASRL?+"?