SledBuild for Sandbox

I’m sure you’ve probably seen Vanoss and the crew play SledBuild on the sandbox gamemode. If you haven’t, look it up on YouTube, it’s funny as hell!

Anyway, I’d like to be able to use the SledBuild map on the sandbox too so that there are no limits to the props that can be used, and there are no annoying bell tolling sounds for each race… However, whenever I go onto the sandbox there is an invisible barrier hidden within the visible glass barrier. There is also a problem where the snow isn’t actually slippery so nothing can slide along it.

Does anyone know how to remove/open the barrier (I think if it is opened then that might activate the slipperiness) and how to activate the slipperiness of the snow?