Hello !
Judging by the following link, you may never correct your problem :
http://www.experts-exchange.com/OS/Microsoft_Operating_Systems/Server/Windows_Server_2008/Q_24474964.htmlNo one ever found a solution for this problem, which is really, really similar to yours.
I would go with a workaround. Set up your task to launch a batch file instead of send an email and get your hand on the "sendemail.exe" command line email sender (see here :
http://caspian.dotconf.net/menu/Software/SendEmail/). You can then pass parameters to your batch file to personalize your message. I works great, I've been using this for years. This should solve your problem.
Syldra