The selected stored procedure returns no columns, when i try to import my stored procedure inside my asp.net mvc

I have the following stored procedure inside my SQL server 2008 r2 & asp.net mvc web application :-

USE [ITSERres]
GO
/****** Object:  StoredProcedure [dbo].[AdvanceSearchSP]    Script Date: 08/04/2014 16:21:12 ******/
SET ANSI_NULLS ON
GO
SET QUOTED_IDENTIFIER ON
GO
/****** Object:  StoredProcedure [dbo].[AdvanceSearch2]    Script Date: 07/18/2014 10:37:47 ******/


ALTER PROCEDURE [dbo].[AdvanceSearchSP]
        -- Add the parameters for the stored procedure here

        @SearchType nvarchar(10) = null,
        @CustomerID bigint = null,
        @StringCustomerID nvarchar(50) = null,
        @SiteID bigint = null,
        @StateID bigint = null,
        @PrimarycustomerOnly bit = false,
        @RoleID int = null,
        @TypeID int = null,
        @IsManaged bit = null,
        @Name nvarchar(125) = null,
        @NameSelection nvarchar(10) = null,
        @Tag nvarchar(50) = null,
        @TagSelection nvarchar(10) =null,
        @ServiceTag nvarchar(100) = null,
        @ServiceTagSelection nvarchar(10) =null,
        @SerialNumber nvarchar(50) = null,
        @SerialNumberSelection nvarchar(10) =null,
        @Comment nvarchar(250) = null,
        @CommentSelection nvarchar(10) =null,
        @IP nvarchar(50) = null,
        @IPSelection nvarchar(10) = null,
         @MAC nvarchar(50) = null,
         @MACSelection nvarchar(10) = null
    AS
    BEGIN

        SET NOCOUNT ON;
if(@SearchType = 'name')
Begin 
        -- Insert statements for procedure here
    select t.Tag , r.RESOURCENAME , rs.DISPLAYSTATE as StateName, tt.Name as TypeName , sdo.NAME as sitename , accountdef.ORG_NAME as cusotmername, t.IsManaged as ismanaged ,sysinfo.SERVICETAG,r.SERIALNO
  //code goes here...

I did the following:-

1. i mapped the SP insdie my .edmx file.

2. i right click on the .edmx file, click on "Model Browser".

3. under my Model, i click on function Import.

4. I right click on the SP , click on edit. then when i click on "Get Column Info" , i got the following message:-

The selected stored procedure returns no columns

so can anyone advice ? Thanks