[Zope-dev] Using Pyrex (with BTrees)?

Has anyone tried to use Pyrex with BTree datastructures? I tried to use Pyrex to optimize a bottleneck in TextIndexNG3 where an iteration over a list of word ids (and insertion into an IOBTree) takes very long. Unfortunately the C extension produced by Pyrex behaves differently from the original code because several unittests do fail...anyone with similar experiences? Andreas