Outlook Conector GAL defaults to RTF format for emails

Using Outlook 2010 on Win 7 Pro 32 bit
ZCO Outlook connector ZimbraConnectorOLK_7.2.1.529_x86
zcs-NETWORK-7.2.0_GA_2669.RHEL6_64.201204100021177

Question: Is there a way to set the "Internet Format" of GAL contacts on either the Zimbra server, or have them default to HTML or Plain Text in Outlook.

Explanation:

Trialing a mixed client environment with Outlook, Thunderbird, Mac etc


Outlook client "options" set to compose mail as HTML, and convert to HTML for Internet recipients.

When composing an email in Outlook to another "internal" zimbra user, using addresses from the GAL , message is sent as RTF format.

As we are using a mixed email client setup, attachments are showing up as winmail.dat in Non Outlook clients.

Checking the internet options for the contact in the GAL shows the Email Type as "Custom" and the Internet format as "send using Outlook Rich Text Format"

You cannot change the settings as the GAL contacts are read only.

In an Outlook only environment, this is not an issue, but in a mixed environment (One of Zimbra's main benefits) This is causing frustration.

Help/Suggestions appreciated.

Well, after some digging I have found a solution to the Outlook RTF issue when using the GAL.

It appears that Outlook treats all users in the GAL with the same default behavior as if they were an 'Exchange' account.
So it sets the mail format to RTF

In Outlook you can set a registry entry to force Outlook to NOT use RTF at all.

For Outlook 2010 the entry would be

[HKEY_CURRENT_USER\Software\Microsoft\Office\14.0\O utlook\Preferences]
"DisableTNEF"=dword:00000001

that is, Create a DWORD key in HKEY_CURRENT_USER\Software\Microsoft\Office\14.0\O utlook\Preferences
Call it DisableTNEF
Set it to a value of 1


To disable this feature, set the value to 0 or delete the key.

For other versions of Outlook, the Key is basically the same, you just need to specify the appropriate version number in the tree (2010 - 14.0)