*sigh*
The idea is when using a light tent, or anything really background or otherwise, is to shoot the thing for real, as if what comes out of the camera is the finished article.
Bugger the glass for the time being, dont photoshop nothin, shoot the damn flower with a white background and no shadow using the light/reflectors/light tent you have.
This is what its all about, nobody said it was easy, I cant tell you how much more you'll learn by doing it properly.
Now I see your 2nd attempt, I think you allready upped the brightness in the first one, and it didn't work did it, the result will be the same with the 2nd one because you simply dont have enough light in the background.
Equipment can be a limiting factor, but photoshop puts the brakes on any kind of photographic learning process.
You will need to do some minor adjustments in an edit program, IMO photoshop is by far the biggest barrier to photo competancy you will ever have to deal with.
and it makes my arse itch....soooo bad..