[tex-live] kpsewhich can't find mpost.mem

[Elie Roux]

Hello,

I'm trying to build a package that enables LuaTeX users to write 
metapost code in their documents with the MPLib. In order to do so, I 
need to tell Lua where mpost.mem (or metafun.mem) is. The usual solution 
in these cases is to call the lua function kpse.find_file. The problem 
is that it doesn't find it, though the file exists, and kpsewhich (not 
in lua, the true one) doen't find it neither, even with

kpsewhich -format mem -must-exist mpost.mem

It does it in TeXLive 2007 for debian/sid and TeXLive 2008 for Windows.

Is there a workaround to get the path of mpost.mem with kpse? If not 
would it be possible to add something in TeXLive 2009 so that kpse can 
give the path of the mem files?

Thank you in advance,
-- 
Elie