Forum OpenACS Q&A: ad_form trouble creating text select

ad_form  -name filtri_bk -form {\
    {bk_fatture_f:text(select) \
     {label bk_fatture_f} \
     {options {10 20}} \
     {value {10 20}}}}

give the following html code:

<select name="bk_fatture_f" >
<option value="">10</option>
<option value="">20</option>
</select>

I would like to have values in value field like following snippet:

<select name="bk_fatture_f" >
<option value="10">10</option>
<option value="20">20</option>
</select>

Is there a correct way to use ad_form in order to accomplish
this request?

Thanks a lot