>>6140100Uh, it's not very straight-forward. It's done with this attachment that I designed and hand-crafted by stacking and gluing sheets of Styrene (after cutting them into shape/size). Everything was done on-the-go so I have no drawings to replicate it... Maybe you can design and 3D print your own one if you're handy.
Since you have two Shockblasts you can also just have the claw arms hold the Legends one...that was my original plan.