You could use Open Office (Calc) to seamlessly import/export with the utf8 - works pretty-much the same of Excel.
If you really need/prefer excel, copy and paste over (and back to calc)
Hikashop is a great product, and the utf-8 issue is not unique to Hikashop and is experienced in other web components and cross other CMS.
I have used Hikashop for many years and found the component, and those people behind it VERY professional; so the assertion they are otherwise is not accurate.
PS... my import issue has been resolved Nicolas... it was operator error in that I had not selected the UTF-8 at the import stage