Чтобы при наборе виртуального продукта не приходилось руками вбивать имя файла(вместо поля появляется select с именами всех файлов в каталоге /download):
Немного неуклюже и громоздко, но работает.

Файл:
categories.php

После:
<?php
    }
  } elseif ($action == 'new_product') {

Добавить:
   $array[]="";
    $array_rev[]="";
    $index=1;
    define('DIR_FS_DOWNLOAD', DIR_FS_CATALOG . 'download/');
    $dir_handle = @opendir(DIR_FS_DOWNLOAD) or die("Unable to open download");
    while ($file = readdir($dir_handle)) {  
    if($file == "." || $file == ".." || $file == "index.php" || $file==".htaccess") {continue;}
     else{
      $array[$file]=$index;
      $array_rev[$index]=$file;
     $index++;
         }
    }    
    closedir($dir_handle);

После:

<?php if (DOWNLOAD_ENABLED == 'true') { ?>
                <td align="center">
                   <?php
вместо
echo tep_draw_input_field('filename[' . $rows . ']',
$attributes_download['products_attributes_filename'], 'size="12" id=filename[' . $rows . ']');

Прописываем:
                   
                   echo "<select  name=" filename[" . $rows . "]"  id="filename[". $rows . "]"";
                          $option="";                      
                           $tabindex= $array[$attributes_download['products_attributes_filename']];
                           for ($i=0;$i<sizeof($array);$i++){
                           $option.="<OPTION ";
                           $option.=" VALUE="".$array_rev[$i]."">".$array_rev[$i]."</OPTION>";  
                         }
                        echo " >".$option."</select>";
                    ?></td>


Файл:
new_attributes_include.php

После:
<INPUT TYPE="HIDDEN" NAME="action" VALUE="change">
<?php
Добавляем:

    $array[]="";
    $array_rev[]="";
    $index=1;
    define('DIR_FS_DOWNLOAD', DIR_FS_CATALOG . 'download/');
    $dir_handle = @opendir(DIR_FS_DOWNLOAD) or die("Unable to open download");
    while ($file = readdir($dir_handle)) {  
    if($file == "." || $file == ".." || $file == "index.php" || $file==".htaccess") {continue;}
     else{
      $array[$file]=$index;
      $array_rev[$index]=$file;
     $index++;
         }
    }    
    closedir($dir_handle);

После:
if($dl_line['products_attributes_filename']=='')
                    {
                      $dl_line['products_attributes_maxdays']=DOWNLOAD_MAX_DAYS;
                      $dl_line['products_attributes_maxcount']=DOWNLOAD_MAX_COUNT;
                    }

Вместо:
echo "<TD class="main" align="left"><input type="text" id="" . $current_value_id . "_dlfile"  name="" . $current_value_id . "_dlfile" value="" . $dl_line['products_attributes_filename'] . "" size="10"></TD>";

Прописываем:
                        echo "<TD class="main" align="left"><select  name="" . $current_value_id . "_dlfile" value="" . $dl_line['products_attributes_filename'] . """;
                          $option="";                      
                           $tabindex= $array[$dl_line['products_attributes_filename']];
                           for ($i=0;$i<sizeof($array);$i++){
                           $option.="<OPTION ";
                            if ((strlen($dl_line['products_attributes_filename'])>0)&&($i==$tabindex)){$option.=" SELECTED ";}
                           $option.=" VALUE="".$array_rev[$i]."">".$array_rev[$i]."</OPTION>";  
                         }
                                    
                         
                        echo " >".$option."</select>";

                        echo " </TD>";

Файл:
products_attributes.php
После:
 $action = (isset($_GET['action']) ? $_GET['action'] : '');
if ($_GET['action'] == 'update_attribute'){

Добавляем:
    $array[]="";
    $array_rev[]="";
    $index=1;
    define('DIR_FS_DOWNLOAD', DIR_FS_CATALOG . 'download/');
    $dir_handle = @opendir(DIR_FS_DOWNLOAD) or die("Unable to open download");
    while ($file = readdir($dir_handle)) {  
    if($file == "." || $file == ".." || $file == "index.php" || $file==".htaccess") {continue;}
     else{
      $array[$file]=$index;
      $array_rev[$index]=$file;
     $index++;
         }
    }    
    closedir($dir_handle);
}


После:
<td colspan="8">
              <table>
                <tr>
                  <td align="right"><?php echo TABLE_HEADING_DOWNLOAD; ?>&nbsp;</td>
                  <td align="right"><?php echo TABLE_TEXT_FILENAME; ?></td>
                  <td align="right">
                  <?php
вместо:
echo tep_draw_input_field('products_attributes_filename', $products_attributes_filename, 'size="35"')

Прописываем:
echo "<select  name="products_attributes_filename" value="" . $products_attributes_filename . """;
                           $option="";
                           $tabindex= $array[$products_attributes_filename];
                           for ($i=0;$i<sizeof($array);$i++){
                           $option.="<OPTION ";
                           if ((strlen($products_attributes_filename)>0)&& ($i==$tabindex)){$option.=" SELECTED ";}
                           $option.=" VALUE="".$array_rev[$i]."">".$array_rev[$i]."</OPTION>";  
                          }
                          echo " >".$option."</select>";





После:
<td><?php echo TABLE_TEXT_FILENAME; ?></td>
                  <td>
Вместо:
echo tep_draw_input_field('products_attributes_filename', $products_attributes_filename, 'size="35"');

Прописать:
echo "<select  name="products_attributes_filename" value="" . $products_attributes_filename . """;
                           $option="";
                           $tabindex= $array[$products_attributes_filename];
                           for ($i=0;$i<sizeof($array);$i++){
                           $option.="<OPTION ";
                           if ((strlen($products_attributes_filename)>0)&& ($i==$tabindex)){$option.=" SELECTED ";}
                           $option.=" VALUE="".$array_rev[$i]."">".$array_rev[$i]."</OPTION>";  
                          }
                          echo " >".$option."</select>";