Set value doesn,t return the value CI 2.0

[eluser]JuanitoDelCielo[/eluser]
I have one form to search

Code:

<?php echo form_open($search); ?>
<fieldset>
&lt;?php echo form_label('q', 'Buscar', array('class' => 'a-hidden')); ?&gt;
&lt;?php
$input = array(
'class' => 'text fl',
'name'  => 'q',
'value' => set_value('q', 'Search')
);
echo form_input($input);
?&gt;
</fieldset>

And it works, and using the profiler I know the value

POST DATA
$_POST['q'] Search String

So the input field should have the search String but it always show Search

Any ideas?