Sorting with threads in Gnus

[N. Raghavendra]

I have

(setq gnus-thread-sort-functions
     '(gnus-thread-sort-by-number (not gnus-thread-sort-by-date)))

in my Gnus init file.  This sorts threads the way I want --- decreasing
order of dates, latest to earliest.  However, it seems to sort messages
within a thread also in decreasing order of date, as in this example
from the gmane.emacs.help group:

01 2013-07-07 02:48   Chris Seberino         > Trouble binding Alt ...
02 2013-07-07 10:38   Chris Seberino         |-> 
03 2013-07-07 18:21   Pascal J. Bourguigno   | |-> 
04 2013-07-08 02:20   Chris Seberino         | | \-> 
05 2013-07-08 03:36   Pascal J. Bourguigno   | |   \-> 
06 2013-07-07 17:54   Raffaele Ricciardi     | |-> 
07 2013-07-07 09:19   Yuri Khan              |-> 
08 2013-07-07 08:14   Bob Proulx             |-> 
09 2013-07-07 03:51   Peter Dyballa          |-> 
10 2013-07-07 03:46   Pascal J. Bourguigno   |-> 

I want the messages in the thread and each subthread to be sorted in
increasing order of date, like this:

01 2013-07-07 02:48   Chris Seberino         > Trouble binding Alt ...
10 2013-07-07 03:46   Pascal J. Bourguigno   |-> 
09 2013-07-07 03:51   Peter Dyballa          |-> 
08 2013-07-07 08:14   Bob Proulx             |-> 
07 2013-07-07 09:19   Yuri Khan              |-> 
02 2013-07-07 10:38   Chris Seberino         \-> 
06 2013-07-07 17:54   Raffaele Ricciardi       |-> 
03 2013-07-07 18:21   Pascal J. Bourguigno     \-> 
04 2013-07-08 02:20   Chris Seberino             \-> 
05 2013-07-08 03:36   Pascal J. Bourguigno         \-> 

This is the way it is on the Gmane page of the thread at
http://thread.gmane.org/gmane.emacs.help/91990 (with the time zone 3.5
hours behind the time zone above).  Is there a way to get this
Gmane-like order (main threads decreasing, all subthreads increasing) in
Gnus?

Thanks and best regards,
Raghavendra.

PS: I posted this to the gmane.emacs.gnus.user mailing list several days
ago, with no response.  I am posting this here in case some one here has
suggestions.

-- 
N. Raghavendra <raghu@hri.res.in>, http://www.retrotexts.net/
Harish-Chandra Research Institute, http://www.hri.res.in/