It worked!!!!!!!!! :)

This is my test

declare @tnCartID int 

EXECUTE USP_Insert_ShoppingCartInfo 
	'11111111111'  ,
        5 ,
        'Test' 	,
        'B' ,
	'Test selection' ,
        '1,2,3' ,
        @tnCartID OUTPUT

and it returned 1 row affected, 1 row affected.

(I would not mention the fact, that I created this SP at first in master database by mistake :))

Now, how can I see return value and output parameter?