Using system.byte[] in map biztalk 2006

Hi
when you using a byte[] into map, you make or in script functoid or in dll .net this:
public string GETXXX(string fileurl)
byte[] content = null;
try
    {
     System.IO.FileInfo file = new System.IO.FileInfo(fileurl);
      content = System.IO.File.ReadAllBytes(file.FullName);
       }
       catch (Exception ex)
      {
       content = null; //optional , your logic ....
       System.Diagnostics.Debug.WriteLine(ex.Message); //optional
       }
return System.Convert.ToBase64String(content); //this is the code right!! into the map the destination field is a BINARY but you pass a string converted!

bye