pass value to editor on a column with values from other columns

I have a column with
'render: function (data, type, row) {
return (data.EMPRESA + '@' + data.CD_MAQ + '@' + data.DT_INI_ARTG);
}'

But in editor i get [object object] .

http://www.quad-systems.pt/QUAD_PRS/#ajax/prs_articles.php

Please click a row on first table and edit a result on botton table.

Thanks