Enumerate outcomes of Sampling without order, but with replacement

Draw k times from {1,2,..,n}, but return each drawn element -- which unique combinations are there?

Given a set
S = {1,2,...,n},
nreplace(n,k) returns a matrix, each row of which represents a possible outcome of selecting k elements from S, while one element can be selected multiple times. See e.g. the Example at the bottom of http://en.wikibooks.org/wiki/Probability/Combinatorics#Partitions.
The implementation is recursive, using a nested function, so it will only run on Matlab Version 7 and upwards.