Superscript problems with Kindle/Kindle DX

Hi all

I'm having problems with a job which requires ePUB and mobi files - the superscript elements (endnote markers) are causing larger than normal gaps between the lines in Kindle Previewer when viewing as Kindle or Kindle DX devices. Other Kindle devices and the ePUB is fine.

Initially I was making text superscript by using a span tag (class="superscript") and using the usual CSS declarations which I use successfully for ePUB to make it superscript. This didn't work for the old Kindle devices so I tried the <sup> tag, with and without CSS to try and solve the problem but without success.

Does anyone have some magic CSS which will solve the problem for old Kindle devices? I've looked around the web a lot and seen lots of discussion of this issue but no solutions.

If it is not possible I will just have to have the endnote markers non-superscript (eg, [1], [2] etc) but would be happier with superscript ones.

thanks,
Iain