How to add "BDC Wildcard Filter" to the ReadList method

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C#

SharePoint

Situtation:
In SP, I've a customer list with a external data field. In the solution I have a BDC Model with an entity which contains a "ReadItem" and a "ReadList" method. When I deploy my feature and set the object permissions, I can read the Item without troubles. Now i have to search an item. I follow this instructions to create a Filter: http://msdn.microsoft.com/en-us/library/ee471425.aspx but it doesn't work, because I have always the same value in my parameter ("**") ..

Question:
How can I assign the search input to the parameter? Or what's wrong?

Code:

public IEnumerable<Oppertunity> ReadList(String inputParameter)
        {
            using (CRMDataClassesDataContext db = new CRMDataClassesDataContext("server=xxx;database=xxx; uid=xxx ;pwd=xxx"))
            {
                List<Oppertunity> oppertunities = new List<Oppertunity>();
                    
                    var q = from c in db.Opportunities
                            where c.Name.Contains(inputParameter)
                            orderby c.Name ascending
                            select new Oppertunity
                            {
                                OppertunityId = c.OpportunityId,
                                Name = c.Name,
                            };

                    foreach (var o in q)
                    {
                        Oppertunity oppertunity = new Oppertunity();

                        oppertunity.OppertunityId = o.OppertunityId;
                        oppertunity.Name = o.Name;

                        oppertunities.Add(oppertunity);
                    }
                }

                return oppertunities;
            }

Thanks for help a man in education!