Office Docs prompt for Client Certificates.

Our recent discussions with Microsoft about this issue affects the following Client configurations
WinXP running Office 2007
WinXP running Office 2010

Windows 7 running Office 2007
Windows 7 running Office 2010

KB 899927 highlights a workaround in the "Workaround" section of the article under the title "Hyperlinks from Internet Explorer to Office" Essentially though we would add a Custom HTTP Header "Content Disposition" with a value of "attachment" to all Client Confirmation (virtual folder : confirm) folders to achieve this.

This workaround allows our clients the ability to open Microsoft Office Documents (as well as any others in the confirm virtual folder) via a standard File Download prompt as seen below

Currently the only drawback - as detailed in the article KB899927 - is that any Office document will open in the Internet Explorer Temporary File cache read-only. When a user attempts to "Save" this document an error will be generated ( shown below - due to the read-only attribute of the IE Temporary File cache) and prompt the user with a Microsoft Office save error and when they clear the error another prompt (shown below error pic) will ask if they wish to try the save again. If the user still wants to save the opened document - they are given a dialogue to select a local path to now save the file successfully.
(Similar to the dialogue given if the user chooses not to open the document but simply wishes to save it)

Error

Retry

Please review the articles and should you have any comments or suggestions please let Nathan and/or I know directly.

Thanks !