fs-cifs can't specify the account domain

When trying to connect to samba server participating in a
Microsoft Network Domain,

fs-cifs seems to have domain “QNX” hardcoded, which the Samba
smbd rejects the username as

[2003/10/30 06:25:55, 1] smbd/reply.c:check_domain_match(497)
check_domain_match: Attempt to connect as user kabe from domain QNX denied.

Is there any hidden option to change this?

Windows recognize “EXPLICITDOMAIN\username”
but fs-cifs doesn’t have this feature.