I just starting using SQL Server 2008 and with it the auditing feature. I come across the same problem you are having but possible it is different after all.

I noticed that if you audit a select on a table and you execute a stored procedure that performs a select on that particular table, the statement is the query with @parameterName instead of the parameter value. Now if you remove that audit and add execute on that stored procedure, the statement is correctly. However goes well when you perform the execute in SQL Server Management Studio, I can't seem to have the same result if I execute a stored procedure from a .NET application where I am using System.Data.SqlClient with System.Data.CommandType.StoredProcedure.

So if someone can help me (us) out, is glad to do so.

Thanks.