They have the Quick release adapter which lets you use tools from their older upright on our V10. I don’t think they offer anything the other way around.  

Maybe you can get an after market part?

Thanks. I didn’t think it could go that far back. I’ve no found an aftermarket adapter yet

I’ve not seen or found a tool that allows you to use cordless tools on a corded product. Their newer upright have the same connector, I guess they decided that was good enough.