Uniqueidentifier Param Inside A SQL String

I have a uniqueidentifier probleme when i want to execute my sql string. The "PortalID" is my uniqueidentifier passed on my StoredProc parameter. But i cant make it work. It said that i cant add a nvarchar with a uniqueidentifier.!!

what is the best way to do it!!  i try to convert(nvarchar(40), @PortalID) but its not workingdeclare @sql nvarchar(4000)
set @sql = 'select
t.[PortalID],
t.[City],
t.[Name],
t.[Code],
ts.*
from [Hockey_Team_Statistics] ts inner join [Hockey_Teams] t on (t.[TeamID] = ts.[TeamID])
where ts.[SeasonYear] = '+CONVERT(nvarchar(10),@SeasonYear)+' and ts.[LeagueMode] = '+CONVERT(nvarchar(1),@LeagueMode)
+'t.[PortalID] = '+@PortalID+'

order by '+ @SortExpression +''

exec sp_executesql @sql