Thanks for the advice Already have my visor back a like a couple of mm.
But not, it's not a Don Post as it'd be way to small (I tried it once, couldn't get it past my fronthead).
I think the best will be the AC

Hey lads, I made a couple of troops now in my new Royal Guard Costume, and there is one thing I wish to change to the costume: get a ventilation system in the helmet. So I'd like to get your ideas about how to do this, as once there's my head in, I have almost no place left on the top, and I can't p...

Well ok, now I get what you mean.
In France you said, hu ? Well I'm swiss, so it isn't this far... Maybe I shall contact him. Or ask Lucas about this case. The trick seams to come from the collar which seems quite big on Steff-Han.
And in addition, he speaks french... all good for me.

Okey guys thanks for those infos.

Jester, I really don't get what do you mean by drapeyness, so doesn't the translator Could you explain me what you mean ?

Hi ! I wanted to know if anyone has already done his guard using a Fenixprop Robe (they can be found there : http://stores.ebay.com/Fenixprops/Royal-Guard-/_i.html?_fsub=11914253&_sid=403021209&_trksid=p4634.c0.m322 ) Are those robe in the correct color scheme and accepted within the 501st ?...