I think vetoed trades are supposed to get sent to CBS for final review. If the trade is "fair", they generally override the veto.
However, based on my experience, they seem unwilling to override the league view, which is why I stopped playing.
But the 4 votes is just 50% of the non-involved owners - very similar to other veto situations. But if they actually start to follow their rules, I'd think your trade should get put through, though it may take a couple days.