Actually, I just did one more code review of myself, and somehow missed that I submitted the version with the wrong oid. The oid used in the first version is wrong (10000) and was from before I read the docs on properly picking one.
Attached is the fixed version. (hopefully with the right mime-type and wrong extension. Alas, gmail doesn't let you set mime-types; time to find a new email client...)
- Matt K.