texexec+mpost cmr10 vs CMR10 trouble using dvips backend

[Sanjoy Mahajan <sanjoy@mrao.cam.ac.uk>]

A font-embedding issue puzzles me.  First I make a metapost figure that
uses plain tex for the label, so it uses cmr10.  Then I include it in a
context document to get a .ps file.  The problem is that the label shows
up in Courier (which ghostscript uses when it cannot find the font, I
think).

Here is the test.tex 

  \starttext
  \externalfigure[fig.1]
  \stoptext

and this fig.mp

  beginfig(1)
  label(btex hello etex, origin);
  endfig;
  end

The commands are:

  mpost fig
  texexec --ps test
  gv test.ps

The resulting fig.1 has these lines:

  %*Font: cmr10 9.96265 9.96265 65:912
  ...
  (hello) cmr10 9.96265 fshow

and test.ps has

  %%DocumentFonts: LMRoman12-Regular CMR10

But there's no cmr10 (lowercase) embedded in test.ps.  If I generate
test.pdf directly (with texexec test), then all is well.

Is there a magic option or map file line that I need?

[ConTeXt  ver: 2007.03.19 11:20 MKII  fmt: 2007.4.12]

Thanks for any suggestions!  The reason I'm using dvi and ps is that
arxiv.org cannot handle ConTeXt submissions directly.  A workaround
recommended by the arxiv.org maintainers is to submit document.ps with
all the source files in a separate directory (but it won't let you
submit document.pdf with all the source files, a behavior that the
admins say is a bug or 'oddity' but not one that they'll fix soon).

-Sanjoy

`Intellectual property is intellectual theft.'