send enter :F

hello, how can i send enter to UNACTIVE process? I already have made proggy that sends your textbox text to it but havent succeeded with sending enter. I tried with Chr$(13), but i found is that it only sends the enter button to there instead off pressing it. Eg. if you send backspace to it then that where i send it got little square after the text instead it would delete one letter. this MAY sound like glitchy D :, ill explain better if it does

i dunno how in hell to do that lol