seamonkey 2.35 (also firefox) code page problems with downloads

I don't know where to post, because it's a general problem with os2 ports.

Go to the webpage:
<http://www.t-platforms.ru/products/corp/tavolga-terminal-tp22bt.html>
and download the pdf file (which contains cyrillic letters and spaces) 
via (PDF) symbol

It results in a filename only with underscores for cyrillic letters.

By changing to cp866 for mozilla application, downloading by simple 
click doesn't work but using context menu "save link location" is doing 
reliably. The resulting file has correct name.

In both cases copying the link ends in:
http://www.t-platforms.ru/images/pdfTavolga_Terminal/%D0%9B%D0%B8%D1%81%D1%82%D0%BE%D0%B2%D0%BA%D0%B0%20-%20%20%D0%A2%D0%B0%D0%B2%D0%BE%D0%BB%D0%B3%D0%B0%20%D0%A2%D0%B5%D1%80%D0%BC%D0%B8%D0%BD%D0%B0%D0%BB.pdf

Broken code page and charsets?

--
Andreas