I've found you need to place the item you want on the rug first... then lock it down raise it.... place the rug underneath it...
Second way... Items like the Candelabra of Souls can not be raised... so I made a small crate placed it on the spot I wanted it on... secured it.... raised it.. put the carpet down.... lowered the crate released it and chopped it.... and viola there it is.
I believe that deeded items can be placed on top of the carpet without problem.
Hope that helps.
If you want a goza under the rug.. place the goza's raise them 1.. then place the carpet on top of the goza's and then get on and off a mount... popping the goza's over the rug ... and lower the goza's... now your rug is "floating" one spot over the goza mats.