I have a problem when the receipt is emailed out. In de_DE the receipt shows up the correct ext_price and sub-total but in fr_FR the ext_price shows up as zero.

How can some aspects of a receipt show zero? and some not?

both locales have the CHF currency.

when you display the receipt within the site the values show up. Its only when it initially emails we see no values in ext-price and subtotal.

Any ideas on how to debug the code when the email is sent out?

(we are using ml8)