thanks alot for your answer, jorn.

you're right about the plugin not relying on IDs, anyway i can't
figure out how to solve my problem.
i tried generating the second block o input boxes this way:
---------------------------------------------------
  $("#add").click(function(){

  var codex = "<div class=\"item\" style=\"border: 1px solid #999;
width: 700px;\">ART # <input class=\"ainput\" type=\"text\" name=
\"art[]\" size=\"50\"><br><br>Description <input type=\"text\" name=
\"descr[]\" id=\"descr\" size=\"50\"><br><br>Color <input type=\"text
\" name=\"colore[]\" id=\"colore\" size=\"10\"></div>";

  $(".mark").append(codex);
  });
---------------------------------------------------
see: http://www.monokraft.com/test/test.html

but just the first 'ART #' works.

if you have any idea to help, you're welcome.

 rino