Change text during checkout process

[mad_dexter]

Hi all. Where are the following text stored from the checkout_shipping.php page:

(i) "No shipping available to the selected country" when shipping costs are not in the tables for the country/zone,
(ii) "Add comments about your order"

I have searched the files for the text, but found nothing. I want to change the text to
(i) encourage customers to contact me for a shipping quote if their pricing for the destination is not listed
(ii) prompt customers to enter a purchase order number.

Thanks.

[mad_dexter]

I had used Windows Search File to search files for the text, and didn't realise it isn't suitable to search for text embedded in php

Easily found with Dreamweaver CS4. All sorted now