i want to build php page to add qmail user.

when i access by browser my user name in linux : abc
when i use vadduser/vdeluser my user name in linux : def
all data added in qmail will be read with roundCube

my PHP page execute this shell script :
"echo -e '$pswd\n$pswd\n' | HOME=. vadduser $user"

the problem :
after opening PHP page then the user is added, but i got error on sPanel to see user list and roundCube to login to inbox since both sPanel and roundCube try to read file passwd.cdb that now is owned by 'def' instead of 'abc'.

i try to make both user in one group but vadduser always give permission 700 to user 'def' so it's useless to join two users in one group ..

is there any option in qmail to leave passwd.cdb as former owner instead change the owner to 'def' ?