I have a question about using XML provisioning to update Order Custom Fields for an existing order.

What would be the format?
Would it be something like this where I have the <order_update> tag & then the <module code="customfields"> tag outside of it and I send that all to the store?
Or do I put the customfield tag inside? etc

<Order_Update order_id="{order_id}">
<OrderDate>
<Day>01</Day>
<Month>01</Month>
<Year>1970</Year>
</OrderDate>
<ShipAddress1>5060 Shoreham Place</ShipAddress1>
<ShipAddress2>Suite 330</ShipAddress2>
<ShipCity>San Diego</ShipCity>
<ShipState>CA</ShipState>
<ShipZip>92122</ShipZip>
<ShipCountry>US</ShipCountry>

</Order_Update>

<Module code="customfields" feature="util">

<OrderField_Value field="ship_intl_addr_1" order="' $ $orderID $ '">297750</OrderField_Value>
<OrderField_Value field="ship_intl_addr_2" order="' $ $orderID $ '">297750</OrderField_Value>
<OrderField_Value field="ship_intl_city" order="' $ $orderID $ '">297750</OrderField_Value>
<OrderField_Value field="ship_intl_state" order="' $ $orderID $ '">297750</OrderField_Value>
<OrderField_Value field="ship_intl_country" order="' $ $orderID $ '">297750</OrderField_Value>
<OrderField_Value field="ship_intl_zip" order="' $ $orderID $ '">297750</OrderField_Value>

</Module>


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Also, I have a question about using <mvt:call> to send a POST request within a Miva page.
What is the correct format for sending the fields​ ?

Ultimately I want to pass in variables, so how would I do that format wise?

Let's say I want to pass in:
l.settings:order:id
l.settings:order:day
l.settings:order:month
l.settings:order:year

And what names would I use to access them in my PHP file that the call is being sent to? "id", "day", etc ?

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Thank you!