As promised my feedback as I got it from the support:
At this current time, this is not an available feature and we only offer support for DH Groups 1, 2 & 5. I'm afraid I do not have any information as to if/when this will be changed.
You can make a feature request by going to the bottom right-hand corner of any dashboard window and sending the request through the "Make a wish" button.
I had already used the "Make a wish" form.
I asked the support for an alternative and if the new MX series is likely to support IKEv2, otherwise we need to ship back our order because we have to comply with certain security standards towards our customers.
How did you guys solve this security 'issue'?
Regards,
Chr1z