I know what you mean....I think it was a Brubaker story but it didn't take place in Winter Soldier...it was the Captain America 65th Anniversary Special and it was written by Ed Brubaker. This is one of those dangling and neglected plots because Brubaker would leave Marvel shortly after this. You can see that Brubaker was clearly implying that there was either an ancestor of Doom's that was a baron or maybe Doom himself time traveling.