Case of attribute values modified on import SGML->FrameMaker 5.5.6

[Jakob Fix]

Hello,

consider this puzzling little problem: I have an SGML document
containing a number of unique ID attributes following this kind of
scheme: id="ABCD.03.55816DE001BDF8FA".

When importing this document into FrameMaker+SGML 5.5.6 (but 7.2
showed the same results), some values are, surpisingly, converted to
"first letter uppercase, rest lowercase", i.e.
    Abcd.03.55816de001bdf8fa

while other values are left as-is.

The import/export rules file doesn't provide different rules for these
attributes. I tried
    id attribute "id" is fm unique-id attribute "Id";

but the result remains the same. The SGML declaration has NAMECASE
GENERAL set to YES (i.e. case is not relevant). I have tried setting
it to NO (case sensitive) which indeed leaves the attribute values
unchanged (but causes other troubles, as the rules file was created
with YES in mind).

However, I wonder if attribute *values* should be affected by the SGML
declaration at all. Ny understanding was that the NAMECASE rule
applies to names and name tokens, such as element identifiers and
attribute names.

Also, I didn't find this behaviour flisted as a bug on the FrameMaker
Annoyances page (which lets me hope there's a solution to it):
http://www.microtype.com/FM_bugs.html

Thanks for any insight in advance.

--
cheers,
Jakob.