First off, you are going to need a can of Zep BS Repellant for the Weber CS person selling you that line of crap!
Just get the latest and greatest set of ash sweeps and do this quick simple and cheap mod.
Get some sheet metal and cut some tabs that you will use to fit into the leg sockets
secure them onto the ash can assembly with 1/8" pop rivets (or machine screws/nuts-bolts etc.)
Assemble the ash sweeps and simply press the tabs into the leg sockets like the new style assemblies.
The pop rivets are hidden out of sight behind the leg sockets so unless you plan on cooking on it rather than entering it in a show and shine nobody but us hacks will know!