toilet in basement bathroom of 60 yr old house appears to have been installed directly onto concrete floor, that is, no flange that i can see, just the two bolts protruding from the concrete floor. so when the toilet is off, all you can see is the hub of the 4 inch cast iron pipe. i got one of those pvc flanges which are supposed to tighten into the 4 inch cast iron pipe, but it doesn`t reach past the hub, which of course is too big for this adaptor to work. any ideas other than breaking up the floor to cut off the flange?