FCKEditor API Character Encoding Issue

I run a Latvian website. My current charset is set to ISO-8859-4.

Now I've noticed that when i type Latvian Characters into an FCK Editor text area and hit submit, it converts my latvian into strange characters.

The code I have is:

window.addEvent('domready', function() {
   $('myForm').addEvent('submit', function(e) {
      var content = FCKeditorAPI.GetInstance('comment').GetXHTML();
      $('comment').setProperty('value',content)
      e.stop();
      var log = $('log_res').empty().addClass('ajax-loading');
      this.set('send', {onComplete: function(response) { 
         log.removeClass('ajax-loading');
         log.set('html', response);
      }});
      this.send();
   });
});

This issue is only present when i use ajax for a form. Standard HTML forms work fine.

Thanks guys