multi-measure rest markup again

[John Williams]

I finally got myself clued in on doing the \roman in my multi-measure rest
marks (because the default font has no letters... DOH!)

So R1*10_\markup{\roman "Tacet"} does work.  Well, sort of anyway.

The markup text actually replaces the normal "10" markup.  What I want is
the "10" centered above, and the "Tacet" left-justified below.  So I
tried:

   R1*10_\markup{\roman "Tacet"}^\markup{"10"}

which doesn't work.  My experimenting leads me to believe that unlike
normal notes, which can have multiple scripts, only the first script is
used by multi-measure rests.  So I cannot have text above AND below the
staff.

Also, the text is \center-ed by default, and I cannot figure out a way to
deactivate that setting.  \column and \line don't do it apparently.

~ John Williams