I am sympathetic, but can't really help. I have one external harddrive, a Seagate, which mounts fine each time. I have another, a Verbatim, which sometimes doesn't mount unless I try different usb ports.
I used to have the authentication problem, with earlier versions of Vector, but don't anymore. Can't recall what I did. Someone on this forum had a idea and it worked. I don't think I reformated either drive. And the problem was more on my end than Vector's.
And I take issue with your concern about VL not being friendly with removable media. VL7 standard, without any modification, mounts everything..my Olympus camera etc without any problems (except the Verbatim) and it eventually recognizes the Verbatim, something my daughter's Apple laptop won't do at all. It wouldn't mount my Kodak camera but that is because Kodak demanded proprietary Microsoft. I gave that camera away and am happy to report that Kodak is now out of the camera business. And I made no modifications to VL 7 to help it recognize removable media. So I suspect that somehow your install didn't go right, that you are not using VL 7, or that you are trying to mount something requiring proprietary software.