As an A.E. speaker, I see both
with respect to
in respect to
...as more common in today's usage than in respect of.
Upon researching the matter, I see that the three forms are highly debated. Nonetheless, the consensus seems to be that all three are equivalent in meaning. I only suggest that many others, like myself, find the wording respect of to be ever so slightly jarring in that it causes some readers to stop and ponder whether the meaning is other than the apparently more familiar respect to, whereas I've found no comments about tripping over respect to. Therefore, I suggest the latter. Also, my ear wants to repeat the helper verb have before met so as to avoid any confusion about its correct reading as present perfect and not simple past tense, which would not concord with the clearly present perfect have fulfilled. Therefore, building upon @escoville's translation, I kindly suggest the following as a refinement:
By confirming, you also declare that you have fulfilled your responsibilities with respect to packaging and have met all other requirements of EN 13427.