index_format

[Fourhundred Thecat]

Hello,

I have following index_format:

  index_format="%{%Y-%b-%d %H:%M} %?X?(%X)&  ? %-25.25F  %.96s %> %5c"

I would like to make following change to the last column, where message
size is shown:

1) if message size is less than 0.1M, show empty column
2) if message size is more than 0.1M show message size, but always in
megabytes (not kilobytes)

can somebody please advise how to do this?