http_sramble unsramble the password

hi

we are using http scramble fm to scramble the ftp user password and then calling ftp server using ftp_connect fm. since few days the connection is failing. ftp server folks say that the password is coming as blank. we have activated rfc trace for sapftpa destination and saw the logfile dev_ftp. in the file the password is mentioned as *****. i am not sure why. before i raise it to sap i want to know if the scrambled password is actually correct or not. to do this i want to unscramble the output of http_scramble FM. how do i do that?