Hi @tonnick
Sorry for the misunderstanding, Joep is a Joomla user so that's why you didn't get the right answer ;-)
WPML is supported and you should be able to see strings in it.
In fact the string is splited in multiple ones.
String is: I agree with the %1$s and the %2$s
Then the params are replaced by the two other translations.
If you still can't see them in WPML please open a support ticket. We will have a look at it