since i made my own mod on a n SPPC oscommerce heavly modified, I'm posting only the hack on coupons_exclusions.php class that was the real issue. Infact the original code cannot deal php and js parameters due to a malformed variable names. Here it is how it can work with both JS function for the 2 mutliple selects and PHP POST.
this patch should work on every Discount Coupons contrib version.
bye bye
/---------------------------------------/
in admin/includes/classes/coupons_exclusions.php
Near line 140 select
from '.tep_draw_form
to </form>
and replace with the following
'.tep_draw_form( 'choose'.$this->type, FILENAME_DISCOUNT_COUPONS_EXCLUSIONS, 'cID='.$this->coupons_id.'&type='.$this->type, 'post', 'onsubmit="form_submission( document.getElementById([\'selected_'.$this->type.'[]\']) )"' ).'
<table width="100%" border="0" cellspacing="0" cellpadding="0">
<tr>
<td align="center" class="main">'.HEADING_AVAILABLE.'</td>
<td align="center"> </td>
<td align="center" class="main">'.HEADING_SELECTED.'</td>
</tr>
<tr>
<td rowspan="5" align="center">'.tep_draw_pull_down_menu('available_'.$this->type.'[]', $this->all_options, '', 'size="20" multiple="multiple" style="width: 300px" id="available_'.$this->type.'[]"').'</td>
<td align="center"><input name="choose_all" type="button" id="choose_all" value="Choose All >" onclick="selectAll( document.getElementById([\'selected_'.$this->type.'[]\']), document.getElementById([\'available_'.$this->type.'[]\']) )"></td>
<td rowspan="5" align="center">'.tep_draw_pull_down_menu('selected_'.$this->type.'[]', $this->selected_options, '', 'size="20" multiple="multiple" style="width: 300px" id="selected_'.$this->type.'[]"').'</td>
</tr>
<tr>
<td align="center"><input name="add" type="button" id="add" value="> >" onclick="updateSelect( document.getElementById([\'selected_'.$this->type.'[]\']), document.getElementById([\'available_'.$this->type.'[]\']) )"></td>
</tr>
<tr>
<td align="center"><input name="subtract" type="button" id="subtract" value="< <" onclick="updateSelect( document.getElementById([\'available_'.$this->type.'[]\']), document.getElementById([\'selected_'.$this->type.'[]\']))"></td>
</tr>
<tr>
<td align="center"><input name="remove_all" type="button" id="remove_all" value="< Remove All" onclick="selectAll( document.getElementById([\'available_'.$this->type.'[]\']), document.getElementById([\'selected_'.$this->type.'[]\']))"></td>
</tr>
<tr>
<td align="center"><input name="action" type="submit" id="action" value="Save"> <input name="action" type="submit" id="action" value="Cancel"></td>
</tr>
</table>
</form>