Søgestreng i storedprocedure fungerer ikke

Hej,

Jeg forsøger at lave en søge funktion, som jeg ikke helt kan få til at lykkes. Håber en eller anden herinde, kan hjælpe mig.....

Først min stored procedure:
set ANSI_NULLS ON
set QUOTED_IDENTIFIER ON
go

ALTER PROCEDURE [dbo].[GetCompanySearch]
    @SearchString AS VARCHAR(200) = null,
    @companyCategory AS VARCHAR(200) = null,
    @companyType AS VARCHAR(200) = null,
    @companyCountry AS VARCHAR(200) = null,
    @companyFullName AS VARCHAR(200) = null

AS
BEGIN
    SELECT  tCompany.fCompanyPId, tCompany.fCompanyAccount, tCompany.fCompanyAlias, tCompany.fCompanyName,
              tCompany.fCompanyAddress1, tCompany.fCompanyfAddress2, tCompany.fZipCodeFId, tCompany.fCompanyState,
              tCompany.fCompanyPhone, tCompany.fCompanyFax, tCompany.fCompanyEmail, tCompany.fCompanyHomepage,
              tCompany.fDimDetailCustomF1Id, tCompany.fCompanyNote, tCompany.fDimDetailCustomF2Id, tCompany.fCompanyCvr,
              tCompany.fCompanyPnr, tCompany.fDimDetailCustomF3Id, tCompany.fCompanyOrder, tDimZipCodes.fZipCodeNo,
              tDimZipCodes.fZipCodeCity, tDimDetail.fDimDetailText, tDimDetail_1.fDimDetailText AS CompanyCategory,
              tCompany.fDimDetailCustomF4Id, tOurContact.fOurContactFirstName + N' ' + tOurContact.fOurContactLastName AS ContactFullName,
              tDimDetail_2.fDimDetailText AS CompanyCountry


      FROM  tOurContact RIGHT OUTER JOIN
              tCompany LEFT OUTER JOIN
              tDimDetail AS tDimDetail_2 RIGHT OUTER JOIN
              tDimZipCodes ON tDimDetail_2.fDimDetailPId = tDimZipCodes.fDimDetailFId ON
              tCompany.fZipCodeFId = tDimZipCodes.fZipCodePId LEFT OUTER JOIN
              tDimDetail AS tDimDetail_1 ON tCompany.fDimDetailCustomF2Id = tDimDetail_1.fDimDetailPId ON
              tOurContact.fOurContactPId = tCompany.fDimDetailCustomF4Id LEFT OUTER JOIN
              tDimDetail ON tCompany.fDimDetailCustomF1Id = tDimDetail.fDimDetailPId

WHERE
(
    ((CAST(fCompanyPId AS VARCHAR(200))) LIKE COALESCE('%' + @SearchString + '%', (CAST(tCompany.fCompanyPId AS VARCHAR(200))))) OR
        (fCompanyAlias LIKE COALESCE('%' + @SearchString + '%', tCompany.fCompanyAlias)) OR
        (fCompanyName LIKE COALESCE('%' + @SearchString + '%', tCompany.fCompanyName)) OR
        (fCompanyAddress1 LIKE COALESCE('%' + @SearchString + '%', tCompany.fCompanyAddress1)) OR
        (fCompanyfAddress2 LIKE COALESCE('%' + @SearchString + '%', tCompany.fCompanyfAddress2)) OR
        (fZipCodeNo LIKE COALESCE('%' + @SearchString + '%', tDimZipCodes.fZipCodeNo)) OR
        (fZipCodeCity LIKE COALESCE('%' + @SearchString + '%', tDimZipCodes.fZipCodeCity)) OR
        (fCompanyPhone LIKE COALESCE('%' + @SearchString + '%', tCompany.fCompanyPhone))

)
AND
(tDimDetail_1.fDimDetailText = COALESCE(@companyCategory, tDimDetail_1.fDimDetailText))
END

Company tabellen indeholder 9 rækker. Nu vil jeg frygtelig gerne at hvis indholdet af @SearchString og @companyCategory er tomme, skal den hente alle 9 rækker fra Company tabellen..... MEN det gør den ikke. Den henter kun de 8, hvor der er skrevet noget i tDimDetail_1.fDimDetailText.

Er det i min FROM eller WHERE sætning, der er et problem - og hvor går det galt  henne?

mvh
simsen :-)