A former junior banker at Merrill Lynch yesterday confessed to of a brazen insider-trading scheme that also enlisted an exotic dancer, a retired Croatian seamstress, a New Jersey mailman and moles inside a BusinessWeek print shop..........the Trans-Atlantic stock fraud scam that racked up $6.7 million in ill-gotten gains....... Trading on tips from the young banker on six big mergers netted $6.4 million of the illicit profits, making it by far the most lucrative scheme concocted by the insider-trading ring's masterminds, Eugene Plotkin, 27, and David Pajcin, 29. The pair, who met while they both worked at Goldman Sachs, recruited Shpigelman...