How to send multiple attachments+body

Hi,
I am trying to send multiple attachments in a single mail with mail?s body. For that I am using following code

Uuencode $a $a > a.mail

Uuencode $b $b >> a.mail

Uuencode $c $c >> a.mail

Echo ?This is system generated mail. Please don?t reply? | Mailx ?s ?this is test mail? abc@xyz.com < a.mail

Though this code is working fine in terms of sending multiple attachments but mail?s body is not coming with mail. i.e. (This is system generated mail. Please don?t reply) is not coming in mail.. )

Tell me how to send mail?s body along with multiple attachments.