Ok, so if I do (and several variations of, eg. minus 'workgroup' and 'ids') I can mount using "mount -a" (as sudo or root) from the fstab line:
<machine_name> <mount_point> cifs credentials=/root/.smbcredentials,dmask=0777,fmask=0777,workgroup=workgroup,gid=500,uid=500 0 0
where /root/.smbcredentials is a file:
HOWEVER, I STILL can't automount from boot. During boot I get the message:
"error 13 opening credentials file"