Sorry it took so long, but other things had a higher priority.
I finally got around to writing a program that will update the current blog’s database with the content from the old database.
This is to correct the import problem that I discovered a few weeks ago.
I really should put together a bug report for wordpress.
Of course it would be even better if there were a mechanism to convert a single site wordpress blog to a multi-site blog, so these kind of issues would be avoided.