It can also be done with a form region manifest, assuming the MessageClass is changed to the custom class: http://forums.microsoft.com/MSDN/ShowPost.aspx?PostID=2199745&SiteID=1&mode=1

Sue Mosher, Outlook MVP
Author of Microsoft Outlook 2007 Programming:
Jumpstart for Power Users and Administrators
http://www.outlookcode.com/article.aspx?id=54

"Ken Slovak - [MVP - Outlook]" <kenslovak@mvps.org> wrote in message news:eEi2m%23AOIHA.1168@TK2MSFTNGP02.phx.gbl...
> With a custom form you can set the large and small icon properties in the
> Properties tab of the item in design mode.
>
> --
> Ken Slovak
> [MVP - Outlook]
> http://www.slovaktech.com
> Author: Professional Programming Outlook 2007
> Reminder Manager, Extended Reminders, Attachment Options
> http://www.slovaktech.com/products.htm
>
>
> <krach.aran@gmail.com> wrote in message
> news:91e30b85-2b7f-43f6-b4fc-14a0f806e6a8@s8g2000prg.googlegroups.com...
>>I am writing a plugin for Outlook 2007 using VSTO SE.
>>
>> The plugin does the following job:
>> It adds a button to a custom ribbon.
>> When the button is clicked the mail is archived, and a footer
>> containing archivation data is added to the mail body.
>> After the mail is Archived i want to add a custom icon (logo of
>> archiving system) to the item in my inbox (next to the Flag and the
>> Category Icon).
>>
>> I can't find any clues on how to implement this functional
>> requirement.
>> Is This Possible ? if yes in what way ? i have looked into both forms
>> and custom fields but are unable to find any clues that it is possible
>> to do this.
>
06 Dec 2007Adding a Custom icon to my inbox.krach.aran@gmail.com
06 Dec 2007\ Re: Adding a Custom icon to my inbox.Ken Slovak - [MVP - O...
06 Dec 2007   \ Re: Adding a Custom icon to my inbox.Sue Mosher [MVP-Outlook]
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