How to increase length of outbound Email subject line using FM SO_NEW_DOCUMENT_ATT_SEND_API1

Hi Frds,

I am using FM SO_NEW_DOCUMENT_ATT_SEND_API1 to send email using document type 'HTM'.

Now concern is I need to increase the size of subject line i.e. more than 50 character.

Please advice.

thanks,

Raj