Automated invoicing - date formats

Hey Guys,

We are a One World customer with subs around the world.  We use the advanced financial module to create sales orders and schedule invoices using predifined billing schedules.

Invoicing is currently a manual process and we are looking to automate this through a nightly script.  We email our invoices out on creation.

This all works fine except for the date format on the generated invoices.  The invoices for our North American sub should be mm/dd/yyyy (which works fine with manual creation) where other subsidiaries should be dd/mm/yyyy.

Is there anyway that I can set the date format to be used when the invoice is emailed?  We basically use the 'To be emailed' check box in the invoice and populate the email box next to it using server side scripting.