FREETEXT problem on stored procedure

my problem is when i enter the text like "XXX" and click search button it shows the record for only "XXX". but i want to show all the records of the Uppercase and also the lower case of "XXX". then i try freetext but it shows "Incorrect syntax near the keyword 'Freetext'".

can anyone tell me the reason......

i'm using the below code for multiple search....

set ANSI_NULLS ON 
set QUOTED_IDENTIFIER ON
go
ALTER PROCEDURE [dbo].[sp_searchdetails] 
    @customervendortype varchar(30)=Null,
    @customervendorid   varchar(30)=Null,
    @customervendorname varchar(30)=Null,
    @state              varchar(30)=Null,
    @city               varchar(30)=Null
AS
BEGIN

if @customervendortype is not null and len(@customervendortype)=0 set @customervendortype = null
if @customervendorid is not null and len(@customervendorid)=0 set @customervendorid = null
if @customervendorname is not null and len(@customervendorname)=0 set @customervendorname = null
if @city is not null and len(@city)=0 set @city = null
if @state is not null and len(@state)=0 set @state = null

SELECT CustomerVendorDetails.customervendorid,CustomerVendorAddressDetails.customervendorname, CustomerVendorAddressDetails.doorno, CustomerVendorAddressDetails.street, 
CustomerVendorAddressDetails.city, CustomerVendorAddressDetails.state, CustomerVendorAddressDetails.country, 
CustomerVendorAddressDetails.pincode,  CustomerVendorDetails.decidingauthority, 
CustomerVendorDetails.landlineno1, CustomerVendorDetails.landlineno2, CustomerVendorDetails.faxno, ContactPersonDetails.contactno, 
ContactPersonDetails.designation

FROM       
CustomerVendorDetails INNER JOIN
CustomerVendorAddressDetails ON CustomerVendorDetails.customervendorid = CustomerVendorAddressDetails.customervendorid INNER JOIN
ContactPersonDetails ON CustomerVendorAddressDetails.customervendorid = ContactPersonDetails.customervendorid

WHERE   
(@customervendortype is null or CustomerVendorDetails.customervendortype like @customervendortype) an开发者_高级运维d  (@customervendorid is null or CustomerVendorDetails.customervendorid like @customervendorid) and Freetext (@customervendorname is null or CustomerVendorDetails.customervendorname like @customervendorname ) and Freetext (@city is null or CustomerVendorAddressDetails.city like @city)and Freetext (@state is null or CustomerVendorAddressDetails.state like @state)

END

in freetext function you needn't do some action just describe column(s) and parameters. see MSDN (second example describe variable usage)