[metapost] DVItoMP capacity exceeded

[roegel at loria.fr]

Dear Metaposters,

I am currently experimenting with including Chinese/Japanese characters
in metapost, and I have met a problem with dvitomp.
When I include too many characters (actually a few may be enough,
for instance 20 Japanese Kanjis), I end up with the following
dvitomp error:

   DVItoMP abort: DVItoMP capacity exceeded (max font numbers=300)

Is this normal and can it be circumvented (other than by reducing
the number of characters used)? In the current state,
it is almost impossible to write any complex thing in Chinese
in metapost.

More details upon request.

Thanks,

Denis