[Groff] confused by soelim

[Robert D. Goulding]

According to info groff, .mso is:

Identical to the `so' request except that `gtroff' searches for the
specified FILE in the same directories as macro files for the the `-m'
command line option

.so is marked with a footnote `see gsoelim' - the implication is that
soelim is needed to read in files specified by both requests.

Also, man groff_tmac (5) make this explicit:

Note that in order to resolve the .so and .mso requests, the roff pre-
processor soelim(1)  must be called if the files to be included need
preprocessing.  This can be done either directly by a pipeline on the
command line or by using the troff/groff option -s.  man calls soelim
automatically.

But, as far as I can see, at least .mso requests do *not* require soelim;
and, in fact, soelim is *unable* to resolve them.  Am I missing something?
I'm asking because I need to know in what order certain local macros and
external files will be read in to a document.  In particular, I have files
of refer definitions between .R1 .R2 requests, each corresponding to a
different journal style; they are kept in my local tmac directory.  I had
hoped that a file beginning

.mso JOURNALXX.tmac \" Refer customization for JOURNALXX

could be processed with the pipeline soelim | refer - but this doesn't
seem to work.  I have to make a symlink to the tmac file in the current
directory, replace .mso by .so and then use soelim.

Robert.

-- 
Robert Goulding
Society of Fellows
Joseph Henry House
Princeton NJ 08544