interface and taxonomy translated, but not the content

I have a web site, recently upgraded from D5 to D6. It uses English as default language, and 2 other languages, that are used most. The content is not translated, as the site is used by bi-lingual community that perfectly reads both languages. While on D5, I only used a feature of interface translation, with users switching language of interface in profile. But, of course, the interface translation was inconsistent, as user-submitted content, such as menus and taxonomies, wasn't translated.

D6 claimed for greater internalization support, so after the upgrade I've set the task to make all menus, block titles and taxonomy translatable, so that all interface can be avaliable in 3 languages, and controlled from user profile or browser language. No content is translatable and all content is shown to all users, no matter what language they've chosen. No url prefixes is set for languages (for it doesn;t really make sense in such configuration, creates duplicate content SEO issue and also breaks many hardcoded links)

So I started from dealing with new behaviour of language negotiation ( http://drupal.org/node/282178 )
The only way to make it work the way I intended was to use crude hack http://drupal.org/node/222401#comment-844115 Any advice on other, more drupalish ways of doing so (except for waiting for D7 release) will be appreciated

Then I tried enabling i18n module and submodules of String translation and Taxonomy translation, to be able to translate taxonomy terms. The immediate effect of this change was that story and blog content type items, created after the D5-D6 shift, stopped showing for most users. The upgrade notes http://drupal.org/node/313315 are not mentioning the case of upgraded site that wasn't using i18n while being version 5.

So I just deinstalled i18n and decided to seek your advice.

Please advise, as i see no valid options apart from hacking modules for extra t()s