how to manipulate multidimensional arrays?

So with the new array objects I can make arrays of any depth but I can't find a way to manipulate the elements of an array more than one level deep. So I can use "replace 2 x" to replace the 2nd element of an array with x, but there is no obvious way to do something like the coll message "nsub 2 5 x" where the 5th element of the 2nd array of the array is set to x, or coll's "nth 2 5" to quickly recall the 5th element of the 2nd array of the array.

I know I can do this with multiple array objects, but it quickly gets unwieldy, especially for higher dimensions. Is there any array method I've missed?