X-Cart forums - Need to add phone numbers for both billing & shipping addresses

Since majority of our orders are gifts we need the customer to enter phone number for both their billing info and also the recipients number under the billing address.

First, what template includes the customer personal information that they fill out when they enter their billing & shipping addresses? I'm assuming that I will need to add for example {$order.s_phone} to this page so the customer can enter the shipping phone number.

Also, I have been editing order_invoice.tpl to format our invoice.

will adding this:

Code:

{if $_userinfo.default_fields.phone}

 <tr>

  <td><b>{$lng.lbl_phone}:</b></td>

  <td>{$order.phone}</td>

 </tr>

{/if}

into each table for the billing and shipping address work or do I need to modify it for the shipping address to be the same format as all the other fields, e.g. use the following for the shipping address. Does adding the s_ to the field automatically become recognizable to x-cart as part of the shipping address if I add {$order.s_phone} to the personal details page?

Code:

{if $_userinfo.default_fields.phone}

 <tr>

  <td><b>{$lng.lbl_phone}:</b></td>

  <td>{$order.s_phone}</td>

 </tr>

{/if}

Or is there more to it than that? Hopefully I'm starting to get an understanding how this whole thing works!

Thanks for any help.