elementtree and entities

[rurpy]

I need to parse little snipits of xml that come from a file
that has a large DTD that defines hundreds or entities.
But when these snipits are parsed (with elementtree.XML())
without the DTD, the entities are undefined and cause a
parse failure.

Is there any way to tell elementtree to not fail on undefined
entities but just return the entity as text? (Or is this something
I have to get the underlying parser to do? How?)

Alternatively, can I supply my own entity mapping to elementtree?
Prepending the large DTD to each little snippit before parsing
seems awfully inefficient.