A little more playing shows that this (incorrect display of Latin1 characters in .html files) is caused by OpenACS reading the contents of such files into a TCL string and then outputting it. TCL 8.x uses Unicode for strings, and this is where the fun starts.
Henry Minsky's AOLserver patches that explicitly set the OutputEncoding and so forth should solve this, at least for sites needing only a single character encoding (eg. Latin1) for the entire site.
I'll try to get an AOLserver 3.3+ad13 RPMset built that includes Henry's patches, and an nsd.tcl that uses the new parameters they provide.
BTW, it seems that this whole thing has been discussed before (ie. I am going over old ground here...!) -- I'd just not realized that the difference in handling .html files was directly related to the TCL 8.x stuff, until I actually read the code where OpenACS deals with serving .html files!
