Paste From Word -- Some spaces disappear

Using CKEditor 3.3.1, trying to paste directly from Word 2003 (using the pastefromword plugin).

Some spaces (by far the minority, but always the same ones) disappear after copy + paste with the paste from word plugin. They also disappear when pasting directly into the CKEditor textarea.

The odd thing is, thoses spaces do show up normally in the paste from word pre-entry textarea in the popup. The spaces also appear normally when pasting to any other program (such as notepad) or file. The spaces are normal (ascii 32) and not preceded by any specific or weird character. No other characters disappear, just some particular spaces. There is no way to tell the difference, in Word, between a "normal" and a disappearing space.

Replacing the space with a new space manually in Word removes the problem, but only if the space is removed first, and retyped afterwards. Doing a find and replace of all spaces, sadly, does not change anything -- nor does a find and replace of spaces to "[SPACE]" (or similar) and then replacing that string with a space again (even when saving and reopening in between). If I replace all spaces by double spaces, none of the spaces disappear -- but that is not a viable 'work-around' for my purposes.

When I save the Word file as an RTF file, copying and pasting from that has the same problem. If I manually edit the .rtf file (to split off the spaces from other characters), then re-open and try again, the spaces don't disappear. But that, obviously, is not a viable solution either...

Here are the .doc and .rtf files which have both 1 space that gets lost, and 1 that sticks (as normal):
http://www.tabun.nl/tmp/test_doc.doc
http://www.tabun.nl/tmp/test_doc.rtf
The space after the '.' disappears.

What's wrong with those files?
What might I do to prevent the spaces in them from disappearing?
Has anyone else run into this problem?