sql server 2005 - Unicode Query in OpenRowSet -

i have stored procedure nvarchar parameters. want returned table using openrowset. when use following codes results incorrect

declare @id int declare @sql nvarchar(max) declare @p1  nvarchar(8) set @id=1 set @sql='select *  openrowset(     ''sqlncli'',     ''driver={sql server};'',     ''exec dbo.usp_test @p1 =''''' + @p1 + ''''')' exec(@sql) 

the openrowset convert query varchar , doesn't execute procedure correctly. seems openrowset execute code this:

exec dbo.usp_test @p1='????????' 

so results incorrect. there option in openrowset resolve problem?

when using nvarchar data need add specific character (n) before string values this:

declare @id int declare @sql nvarchar(max) declare @p1  nvarchar(8) set @id=1 set @sql = n'select *               openrowset(''sqlncli'',                           ''driver={sql server};'',                           ''exec dbo.usp_test @p1 = n''' + @p1 + n''''')' exec(@sql) 

note :
when have '''exec dbo.usp_test @p1 =''''' + 'p1' + '''''' equal 'exec dbo.usp_test @p1 =''p1'' wrong , should '''exec dbo.usp_test @p1 =''' + 'p1' + '''''' 'exec dbo.usp_test @p1 ='p1''