one way to get the file name only would be to create another variable. set it's property, EvaluateAsExpression to True. Then enter the following expression:
REVERSE(SUBSTRING( REVERSE(@[User::filename]),1, FINDSTRING( REVERSE(@[User::filename]) , "\\", 1 ) -1))
replace the @[User::filename] variable in the sample code with your variable that is being populated by the ForEachFile loop.