Yes, there's a bug that isn't fixed until 6.0.2.
The Lotusphere JSP tag presentation I did included a demo of the attachments tag:
http://www-10.lotus.com/ldd/sandbox.nsf/ecc552f1ab6e46e4852568a90055c4cd/f2b47a9f6cb470b585256ccb0063023f?OpenDocument&Highlight=0,ad303
To make progress developing this part of your app, you could use the domtags.jar and domtags.tld from it - but understand that when I hit the same bug you just found, the clock was running and I didn't spec it out, I just coded around it. That domtags.jar was not tested in any way beyond doing the demo itself - which was all local, no corba - so please don't ship with it!