AFIFM (3/12/2009)
...The sample code by Michael also does the job nicely except that it will only generates 5 characters string and I need 64 chracters.
I just assumed you would be able to figure out the simple changes needed to get 64 characters, since it is only necessary for you to do cut and paste.
You should be aware that the other solution posted will only return the following characters, and not letters G through Z:
0123456789ABCDEF