And never, never bless off on something because it launches tomorrow.
This is essentially how I finally got everyone to realize I needed to be involved from the beginning. When I first started at the bank, I wouldn't find out about things until just before they implemented it (and sometimes, even after).
I'd usually end up taking it back to them and say you forgot about this, that, and the other thing, and you absolutely can't offer it until it's fixed. It usually caused everyone to scramble to fix things and caused so much chaos that they now finally come to me at the beginning in order to avoid wasting time.
It takes time, but I kept pushing and finally got my point across (most of the time...)