Question

I don´t understand the tags that configure a custom sales quote. In this code snippet:

    <sales>
        <quote>
            <totals>
                <custom>
                    <class>custom/quote_address_total_custom</class>
                    <before>grand_total,....</before>
                    <after>subtotal,shipping,...</after>
                    <render>....</render>
                </custom>
            </totals>
        </quote>
    </sales>

I want to know what are the posibles values for before,after and render tags and the consecuence to check a custom parameter.
In the example you can see

<before>grand_total,....</before>

Does this mean that my custom quote render later the gran_total are calculate???

Answer 1

the possible values that you can use in the before and after tags are the other tags composing the quote, ie: subtotal, grand_total, tax, shipping, etc… In clear, the distincts totals of the quotes.
And regarding your question:

<before>grand_total,....</before>

Does this mean that my custom quote render later the gran_total are calculate???

no, just the other way around: there you are saying before the grand_total total.

About the <render> tag, I don’t think it is valid in this scope… or maybe it is, I dunno. Anyway, in it you put the block class definition you want it to use, for example:

<render>adminhtml/catalog_product_edit_tab_options_type_text</render>

means it uses the Mage_Core_Adminhtml_Block_Catalog_Product_Edit_Tab_Options_Type_Text class