DSM already has the product up on the site. From how the site reads, they're doing an RSVP style release.
"On Thursday 27th June the DSML E-Shop will be launching a strictly limited stock of the Comme des Garcons Shirt / Supreme Vans. Regrettably, we cannot satisfy every customer who would like to buy. To request the possibility to purchase a pair, please enter your name and email address against the size you would like by clicking 'Notify when launched'. Subscriptions close at 6pm GMT on Wednesday 26th June.
On Thursday 27th June, we will send randomly selected customers a link by email where they will have the opportunity to purchase one per style (maximum of 4 pairs in total) of Comme des Garcons Shirt / Supreme Vans."