I think this should work

exec sp_executesql N'exec sp_UpdateProcessedTrades @vcDeptName, @buySellCoverShortFlag, @customerAccountCounterparty, @shadowAccount, @tradeID',

N'@vcDeptName varchar(5),

@buySellCoverShortFlag varchar(1),

@customerAccountCounterparty varchar(6),

@shadowAccount varchar(4),

@tradeID bigint',

@vcDeptName = 'IF-PM',

@buySellCoverShortFlag = 'S',

@customerAccountCounterparty...