Application Express :: How To Get Unique Element IDs In Manual Tabular Form

I'm trying to get a unique sequential element id for every field in a manual tabular form. Here is the code to generate the form:

SELECT apex_item.hidden(1, lpad(rownum,4,0)) row_num,
apex_item.hidden(2, skillset_demand_id) sdi,    
apex_item.text(3, domain, 20, 20, null, 'f03_#row_num#') Domain,
apex_item.text(4, target, 20, 20) Specialization,
apex_item.text(5, skill, 20, 20) Skill
FROM RI_SKILLSET_DEMAND
WHERE WORK_ID = :P511_WORK_IDAccording to the APEX API manual I should be able to set the attribute id with p_item_id*, which in the example of a text item, is the sixth parameter. In line 3 of the code above, I set the p_item_id to 'f03_#row_num#' after having created row_num in line 1.

The HTML I get is:
<input id="f03_#row_num#" type="text" value="xxxxxxxxx" maxlength="20" size="20" name="f03">
...
<input id="f03_#row_num#" type="text" value="xxxxxxxxx" maxlength="20" size="20" name="f03">What I want is:
<input id="f03_0001" type="text" value="xxxxxxxxx" maxlength="20" size="20" name="f03">
...
<input id="f03_0002" type="text" value="xxxxxxxxx" maxlength="20" size="20" name="f03">
...
etc.

I've tried a lot of things but I can't seem to get parameter substitution inserted into the id attribute so I can get each element uniquely with javascript later.