Having never seen the poster that you speak of, that is a really cool concept!
I got the bottle immediately, but I have to admit that it took me a moment to "see" the glass...It could very well be my screen, though.
Being that you said this is your first attempt (causing me to assume that there will be or are more), here are a couple of thoughts that sprang to my mind (and that I'm sure you've already thought of/about):
Would filling the glass (or using one with a heavier stem) help its shadow translate better?
Or maybe moving it closer to the model (who has an attractive form, btw) might help...?
Perhaps swapping sides with the bottle and glass?
I can't wait to see the next versions!
Damn...I wanna try that...