Slicing in Python 2.3a2

[Sébastien Keim]

I have some troubles to understand how work slicing in python 2.3.
In my examples, I will use the following list:
 >>> A = range(10)

Python 2.3 add a new argument to slice wich can for sample be used to
get only the items at positive indexes:
 >>> A[::2]
[0, 2, 4, 6, 8]
This works also for subslices: A[x:y:z] is equal to A[x:y][::z]
 >>> A[1::2]
[1, 3, 5, 7, 9]

With a negative value you can reverse a list:
 >>> A[::-1]
[9, 8, 7, 6, 5, 4, 3, 2, 1, 0]

But I don't understand the result for a subslice with a negative third 
argument:
 >>> A[1::-1]
[1, 0]
Intuitively, I expected to get:
 >>> A[1:][::-1]
[9, 8, 7, 6, 5, 4, 3, 2, 1]

The numarray package has the same behavior, so I guess it's intentional.
 >>> import numarray
 >>> numarray.array(range(10))[1::-1]
array([1, 0])

Then what is the real semantic for this third argument?