[X-Newbies] Mail acct. setup query

[B.Cornett]

G'day to All

Am hoping for a bit of your X-Guru input on a problem
I've got in Mail v1.3.11 running on OSX.3.9.

A few List servers of late have been having a problem
with my single name addy when posting to list thru the
server, and I've had to add my first initial into my
Mail preferences to get the Post's thru. Only now a
few other List servers are not accepting my posts
because of the added initial, and so, I've tried to
setup another account without the initial (all other
parameters are the same) but Mail won't allow me to
save that configuration (as the server settings are
the same) to be able to use it.
ie for: (1) cornett at xxx.xxx
         (2) b. cornett at xxx.xxx
(*oNly used in Description, Email Address outside the
  "< >" brackets, and Full Name fill in areas of the
  1st. section).
I truly do hope the above is understandable.

What am I doing wrong?, and/or How in the world can
I trick Mail to accept the settings?, and no, I don't
wish to have to use Fast User switching or go into
Mail preferences to change each time I wish to send
a post, nor re-sub with the initial'd settings either.

All advice/help will be appreciated and very welcomed.
TIA

Respectful of GURUs
Bill Cornett
cornettATgolDOTcom
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