Thanks Srinivas for your reply,
i have checked the .htm page in mailheader view, yes there is to_header whcih is type CRMT_IC_EMAIL_RECIPIENT_DATA structure.
but the email id is generating/getting from CL_CMPIC_MAIL_WRAPPER_BASE=>FILL_TO_ADDRESS_ONNEW() method when i check it in debug mode.
so here inside this method i need to do modification
pls let me know how to implement this method.. this is standard class.
Thanks,
venkat