WordPress export

Hallo,
I would like to upgrade my WordPress to newer version. From some reasons I decided to do it via export.

In my old WP instance, I noticed that there is this collation : cp1250_general_ci

So I exported my czech-language blog using function “export” which is accessible directly in WordPress. XML file was created. I found that there is this definition <?xml version=”1.0″ encoding=”UTF-8″?>

I installed new instance of WordPress (2.6.2) on different hosting. There is some self-instalation package (from fantastico). After this installation i noticed, that new database has collation : latin1_swedish_ci

So i used command :
ALTER TABLE wp_posts CHARACTER SET utf8 COLLATE utf8_unicode_ci
and collation in database was changed …

Then I imported XML file from old blog. It shows all post_titles with right czech characters (č,ř,ž,..) during importing.

But when I look at blog, all this character was replaced by “?” and also in database, there was these characters replaced by “?”

So what I should do to correctly import old XML file ?

Thanks much