beaming problem

[Haipeng Hu]

Hello,
  I'm now composing an orchestral work, in which there are plenty of
meter changes such as 5/4 and 6/4. Since I'm blind, I gave part of it
to a teacher, and he told me that the beaming in 5/4 and 6/4 is
incorrect. He told me the beaming must be clear for performance, so
5/4 must be 3/4+2/4, and 6/4 3+3. So, please look at the two pictures
in zipped attachment. The one was directly from Lilypond, and the
other from Sibelius, in which I imported the midi file. The beaming in
Sibelius is correct, while in Lilypond, all 16th notes are grouped as
4th. I checked the time-signature-setting.scm, and found the setting
for 6/4 is wrong. Although the comment says for 32nd notes, the line
below it still groups 16ths as 4ths. Is this a mistake? Could anyone
check the theory book for beaming rules and correct the scm file? I
myself modified it and added 5/4, but don't know whether the problem
has been solved.
Thank you in advance!

Regards
Haipeng