permanent link

Hello all,

I would like to know how to enable the 'permanent link' feature for mhonarc. An 
example is in the following link:

http://www.mhonarc.org/archive/cgi-bin/mesg.cgi?a=mhonarc-users&i=200309100306.h8A36hn15434%40gator.earlhood.com

which incidentally is the only mhonarc page that I could google with the phrase 
'permanent link'. Any help would be greatly appreciated.

Thanks,

Nick