I am using Tridion UI 2012 on our website (which is built using DD4T). The problem we're facing is that the session preview web service does successfully commit the edited content to the session-preview database, but it loses its UTF-8 encoding. So everything is stored with symbols like "Â" etc. The encoding is however maintained in the broker database. It's just the session preview database which contains non-UTF8 text.
I have updated the web.config for the session preview web service with the following but this doesn't have an effect:
<globalization culture="auto" fileEncoding="utf-8" uiCulture="auto" requestEncoding="utf-8" responseEncoding="utf-8" responseHeaderEncoding="utf-8" />
NOTE: This problem only started appearing after we included the following new entry in the same web.config (i.e. session preview web service):
<httpRuntime maxRequestLength="2097151" />