Test vector ECDSA keys invalid?

Hi all,

I'm writing some XML Security code, and found some test vectors for ECDSA
here: http://www.w3.org/TR/xmldsig-core1-interop/interop/xmldsig11/oracle/

When trying to validate the XML files using the supplied certificates,
everything appears to be fine. However, when trying to resign the same XML
documents using the supplied private keys, I can't figure out how to load
them.

The readme states the keys are in "PKCS8 binary format" which I assume
means DER encoding. However, nothing I've tried with OpenSSL seems to load
these and provide sane results. I tried the xmlsec1 application too (
https://www.aleksey.com/xmlsec/) using different parameters (--pkcs8-der,
--privkey-der), but it can't figure out how to load these keys either.

Comparing these keys to same curve similar ECDSA keys I've generated with
OpenSSL in DER format, the test vector keys also appear to be significantly
smaller in file size. Are the keys valid? If they are, can additional
details be provided on how to load them? Perhaps provide them also in a
more explicit PEM format?

Thank you,
-Nachman