What can I do with this non-banking job? Please advise

All, I am looking for some advice here. I was/am targeting post-MBA
associate positions at investment banks. After going far with some of
them, I finally don't have an associate offer. However, I recently got
an offer at a Fortune 50 Corporation in their Treasury group. I could
be doing treasury strategy, risk management, FX hedging or capital markets (more on the debt side) and I do have some say in which part of Treasury I get placed in. I still really want to do investment banking and am hoping to switch to
banking after spending a year in Treasury. I wanted your opinions on
whether this can be done and which area should I go with, that would be
give me the best shot at banking. If the switch can't be done, could I
use any of these roles  as a springboard to a better role in say a
hedge fund? What are the exit opps if any from a Treasury position? Thanks in advance.
Pelbo