Problem during conversion and sending through excel file

Hi,

I have to send two separate internal table's data through two sheets in a single workbook.to specific email users.

I have tried to send through  SO_NEW_DOCUMENT_ATT_SEND_API1  . The xml data are converted and passed as binary data through

objbin in the function module.

But finally when I receive the email, the attachment is containing the xml extension instead of two sheets which should be converted internally i suppose.

Please let me know, if i have missed something in the code or any config is missing in system which is unable to convert it.