Problem - Multipart in mail attachment

[Guest]

Hi,
I ahve developed an application to send mails with attachment to a common
mail box say "(e-mail address removed)".
All the mail that comes to this mailbox will be read by some application.

All my attachments from my web page goes perfectly to the mailbox.
But when the file is opened from the "(e-mail address removed)" hro' web mail, I am
able to see
http://web....../L/1_multipart_xF8FF_2_a.txt/C58EA28C-18C0-4a97-9AF2-036E93DDAFB3/a.txt?attach=1
where a.txt is teh fiel I attached.

Here "multipart" is added automatically to my file name, so the other
application is not able to read from this link.
On the other hand, instaed of attaching the file from my application, if I
send from outlook to "(e-mail address removed)" and open the file, I dont find the
"multipart" in teh link and this file is able to read by other application...

So only from my web page, I am getting this problem.. But the attachment
goes fie to teh box without loss of data, only the link is the problem..

What I am going wrong here..
I used SMTPclient class in sytem.net.

Please give me solution ASAP
Thanks in advance