Hallo Ann-Marie,
I put an answer in the forum (http://moodle.org/mod/forum/discuss.php?d=194168&parent=853027) some days ago.
http://docs.moodle.org/22/en/Email_processing
Infos are in chapter: "Email confirmation or registration words, and how to edit them"
I changed in moodle.php the text for the field "paymentthanks". I made the changes directly in moodle and not in a text-editor. The changes are not yet tested, but I hope I have the time to do it within the next days. ]
It sounds quite logical in the moodle docs, but unfortunately moodle takes still the standard-text for the payment-Information which is send to the customer. All the required files are in moodledata, but moodle ignores them. As I understand it, you don't have to change anything at the enrolment plugin.
I want do modify the e-mail the inform my customers, that the have to go to my online-shop and fill out an order form. Otherwise I get their payment but have no chance to create an invoice.
I hope to get a solution within the next days. If you have any ideas in the meantime, please give me an info.
regards
Georg