Okay, my original question has been clearly answered, so this thread can be closed.
1. I now know about my_vec[0].get() for obtaining the pointer that I needed in this case.
2. I understand that I should not use C-style casts in C++; I have expressed the reason that I used it here, which was to debug the errors that I was getting.
3. Thank you all for the pointers (so to speak) to references on smart pointers in C++; I will indeed be pursuing these references further, to enhance my understanding of how to properly use them!!
4. and once again, I deeply thank the members of this community for your (sometimes gruff, but always helpful) assistance in solving my issues with this language; my earlier posts that led up to this one, were somewhat ambiguous and rambling - that can be a result of not initially knowing quite what I am trying to ask about, and what the correct terminology is... Nevertheless, you pursevered and stuck with me, and I now understand what I need to do, to proceed with my C++ development...

Long Live stackoverflow !!