Thema: formularfelder erst aktivieren wenn ratio aktiv

hallo
ich habe ein kleines problem beim erstellen eines formulars.

in meinem Formular sind 4 ratio buttons und zu jedem ratio sind mehrere imputfelder.
jetzt sollen die imput-felder nur aktiviert werden sollen wenn der dazu gehörige ratio aktiviert ist.

hier mal mein form..

<form name="payout" method="post" action="">

<div class="form_de">
<input type="radio" value="ueb" name="austype">
<span class="f2"><?php echo JText::_('BONI_UBERWEISUNG'); ?></span> <span class="f1dgrey"><?php echo JText::_('BONI_DE'); ?></span>

<div class="az_bl">
<input readonly="" value="" name="de_inhaber" maxlength="50" size="25"><br><?php echo JText::_('BONI_KTOINHABER'); ?><br>
<input readonly="" value="" name="ueb_konto" maxlength="50" size="25"><br><?php echo JText::_('BONI_KTONR'); ?><br>
<input readonly="" value="" name="ueb_blz" maxlength="50" size="25"><br><?php echo JText::_('BONI_BLZ'); ?><br>
<input readonly="" value="" name="ueb_blz" maxlength="50" size="25"><br><?php echo JText::_('BONI_BANK'); ?>
</div>
</div>

<div class="form_eu">
<input type="radio" value="eu" name="austype"><span class="f2"><span class="darkblue"><b><?php echo JText::_('BONI_EU'); ?></b>
</span><?php echo JText::_('BONI_UBERWEISUNG'); ?></span> <span class="f1dgrey"><?php echo JText::_('BONI_AT'); ?></span>
<div class="az_bl">
<input readonly="" value="" name="eu_inhaber" maxlength="50" size="30"><br><?php echo JText::_('BONI_KTOINHABER'); ?><br>
<input readonly="" value="" name="eu_iban" maxlength="50" size="30"><br><?php echo JText::_('BONI_IBAN'); ?><span class="dgrey">(<?php echo $this->params->get('iban'); ?>)</span><br>
<input readonly="" value="" name="eu_bic" maxlength="50" size="30" ><br><?php echo JText::_('BONI_BIC'); ?><span class="dgrey">(<?php echo $this->params->get('bic'); ?>)</span><br>
<input readonly="" value="" name="eu_bank" maxlength="100" size="30"><br><?php echo JText::_('BONI_BANK'); ?>
</div>
</div>
</div>

<div class="clear"></div>

<div class="form_pp">
<input type="radio" value="paypal" name="austype"><span class="f2"><b><?php echo JText::_('BONI_PAYPAL'); ?></b><?php echo JText::_('BONI_TRANSFER'); ?></span><br>

<div class="ffix az_bl">
<div style="float:left;margin-right:10px;">
<input type="text" value="" name="wms_login" size="30"><br><?php echo JText::_('BONI_PAYPAL_ADDRESSE'); ?>
</div>
</div>
</div>

<div class="form_sp">
<div style="clear:both;" class="mt5">
<input type="radio" value="sp" name="austype" ><span class="f2b"><?php echo JText::_('BONI_SPENDE'); ?></span><img width="20" height="9" alt="" class="l4"b src="http://img4.klamm.de/images/itsnew.gif"><br>
<div class="f1dgrey az_bl"><?php echo JText::_('BONI_SPENDETEXT'); ?></div>
</div>
</div>

<div class="clear"></div>


<div class="send">
<?php $allowreceivecopy = $this->params->get('allowreceivecopy',1);
if ($allowreceivecopy){

echo '<label><input type="checkbox" name="receivecopy" id="receivecopy" checked/>'.JText::_('BONI_MAILCOPY').'</label> ';

}
?>

<input type="submit" disabled="" style="width:140px;" value="<?php echo JText::_('BONI_BEANTRAGEN'); ?>">
</div>

</form>

ich hoffe mir kann jemand dabei helfen.