Download File Name Problems w/ MSIE in Windows

I've been having a low level frustration with OPENTBS_DOWNLOAD for a while with MSIE.  Anyway, when I assign a file name, I don't get it.  I don't even get the name of the wordprocessing template I'm using -- rather, I get the name of my php file, with .php replaced by .docx or .odt.  When I use OPENTBS_FILE -- the file name is correctly assigned.

I checked out the demo here:  http://www.tinybutstrong.com/plugins/opentbs/demo/demo.html

Using Safari and OS X, when I download a file I get this:
LibreOffice:  demo_oo_text_2013-12-10.odt
MSWord:  demo_ms_word_2013-12-10.docx

In Windows 7 with IE 11 I get the following:
LibreOffice:  demo_merge.htm
MSWord: demo_merge.htm

I've read some posts about MSIE headers, using no headers and such.  But I just can't seem to get the right combination of this going.  Is there some trick to get windows and IE to download a file name?

Hi Hemocyanin,

I cannot reproduce your problem.
I have IE 11 on Win7 and the two downloads are ok.