Hidden values in menu, is it possible?

[estetico]

Cant make hidden values in menu/list...
Tried everything, not working :-(

code:

<form name="search" action='search.php' method="post" >
<p align="center"><select name="tip" size="1">
<option selected value="001">001</option>
<option value="002">002</option>
</select> <input type="text" name="query_search" maxlength="50" size="24" >

<input type="submit" name="sub" value="Go"></p>
</form>

its a:

i need to make values in menu hidden and selected (2 selected values), so search will work with value "001" and "002", like this

tried make style="visibility:hidden;"
but search work only with value 001

Any help? Thanks!