Outlook 2010. We receive messages with html attachments. Unfortunately not always charset is strictly declared in that attachment. In that cases in preview special chars are not visible (polish letters ąęś etc.). I have tested different encoding (save attachemnt on disk, open in PSPad editor and save as utf-8, iso8859-2 and win1250 encoding files, resend all this files). Olny ISO file displays correctly in Outlook preview.
I have read somewhere that Outlook uses IE engine to render html files in preview. But in Outlook 2007 this attachment is displayed without problems. This is the same computer (windows7, IE9), the same configuration, and the same messages and attachments.
Also in Outlook Express on XP machine no problems with display.
Go to IE and changing its character encoding to fit to the true charset of attachemant over and over... is poor solution. Is there any other?