<dt>
    <input id="p_method_store" value="store" name="payment[method]" title="" onclick="payment.switchMethod('store')" class="radio" autocomplete="off" type="radio">
    <label for="p_method_store"> </label>
</dt>

config.xml
        <payment>
            <namespace_pay>
                <active>1</active>
                <model>pay/payment_store</model>
                <order_status>processing</order_status>
                <allowspecific>0</allowspecific>
                <title>Pay in the store</title>
            </namespace_pay>
        </payment>


system.xml
        <payment>
            <groups>
                <namespace_pay translate="label" module="pay">
                    <label>Pay in The Store</label>
                    <frontend_type>text</frontend_type>
                    <sort_order>670</sort_order>
                    <show_in_default>1</show_in_default>
                    <show_in_website>1</show_in_website>
                    <show_in_store>1</show_in_store>
                    <fields>
...
                <title translate="label">
                    <label>Title</label>
                    <frontend_type>text</frontend_type>
                    <sort_order>3</sort_order>
                    <show_in_default>1</show_in_default>
                    <show_in_website>1</show_in_website>
                    <show_in_store>0</show_in_store>
                </title>

class Namespace_Pay_Model_Payment_Store
    extends Mage_Payment_Model_Method_Abstract
{
    protected $_code = 'store';
    //...