Beta 2 question regarding System.Net.Mail

[Mantorok]

Hi all

I'm sending an SMTP mail message with an attachment, the problem is that
even after the message has been sent I cannot remove the file from disk that
I've attached.

The file is stored in a directory under the web-site and the only time I can
remove/change the file is after the web-app has shutdown.

Any ideas?

Thanks
Kev