German Umlauts (ä,ö,ü,ß) corrupt in HTML Mails sent with Outlook 2013 and OXtender 2 for OpenXchange

Today i noticed that HTML Mails I sent from Outlook 2013 looked like this on the receiver side:

�ffentliche �bereinstimmung m��te sein

The german umlauts (special characters)  were somehow misinterpreted as non-printable characters.
 

The original text was:

"Öffentliche Übereinstimmung müßte sein"

How-I-fixed-it:

Looking at the raw mail source content i recognized, there was a lot of css-stuff in mail which seemed to be added by Outlook automatically.
osoft-com:office:office" xmlns:w=3D"urn:schemas-microsoft-com:office:word" =
xmlns:m=3D"http://schemas.microsoft.com/office/2004/12/omml" xmlns=3D"http:=
//www.w3.org/TR/REC-html40">ft Word 15 (filtered medium)">
link=3D"#954F72">

=EF=BF=
=BDffentliche =EF=BF=BDbereinstimmung m=EF=BF=BD=EF=BF=BDte sein=

-->
I found out, that there's an option in Outlook to tell it to use CSS for formatting or not.

I disabled this option and my HTML mails look OK now.

Office 365, Outlook 2013: OpenXChange OXTender 2 MAPI Mail profile error "oxstor.dll" could not be loaded

Today i installed Office 365 in parallel to my existing Office 2010 on my Windows 8 Computer. Under Outlook 2010 i use OpenXChange OXTender 2 - Version 7.0.62 to sync with OpenXChange Groupware.
After installing Outlook i created a new mail profile. But in Outlook 2013 i can't open the MAPI Folder. Clicking on it an error message Pops up "The Folder could not be expanded.... MAPI was unable to load the Information service "oxstor.dll" ..."

I also re-installed OXTender, but this did not fix it. Under Outlook 2010 the sync is still working fine.

I posted the question here:
http://answers.microsoft.com/en-us/office/forum/office_365hp-outlook/cant-sync-outlook-2013-with-openxchange-because-of/f87f287c-e62a-4e5b-994c-da90769bf00c

https://forum.open-xchange.com/showthread.php?7769-Outlook-2013-quot-Der-Informationsdienst-quot-oxstor-dll-quot-konnte-nicht-geladen-werden-quot

How-i-fixed-it:
The document Outlook OXtender 2 Best Practices states, that it does not work having both Office 2013 and 2013 installed in parallel:
...
Please note that the following is not supported:

• Office 2010 Home and Business test version
• MS Outlook running in a virtual environment (e.g. VMware or Parallels Desktop)
• Using both OL2007 and OL2013
• Using both OL2010 and OL2013

....

I removed Office 2010 from my Computer and re-installed Outlook OXTender again, created a new profile and... it works.

Here you can find the Information:
http://oxpedia.org/wiki/index.php?title=Outlook_OXtender2_Best_Practice