chown -R userA:userA /media/usb/TimeCapsuleA
and
chown -R userB:userB /media/usb/TimeCapsuleB

[Global]
hostname = TimeCapsule
log file = /var/log/netatalk.log
uam list = uams_guest.so, uams_dhx.so, uams_dhx2.so,
zeroconf = yes
save password = yes
mimic model = TimeCapsule6,106
log level = default:warn
log file = /var/log/netatalk.log
hosts allow = 192.168.178.0/24

[default_for_all_vol]


[TimeCapsuleA]
path = /media/usb/TimeCapsuleBackup/TimeCapsuleA/
time machine = yes
valid user = usera
invisible dots = yes
search db = yes
ea = auto
cnid scheme = dbd

[TimeCapsuleB]
path = /media/usb/TimeCapsuleBackup/TimeCapsuleB/
time machine = yes
valid user = userb
invisible dots = yes
search db = yes
ea = auto

[PogoPlug1]
path = /media/usb/PogoPlug1/
cnid scheme = dbd
ea = auto
mac charset = MAC_ROMAN
invisible dots = yes
search db = yes
valid user = userA userB

[OSX-Exchange]
path = /media/usb/OSX-Exchange/
cnid scheme = dbd
ea = auto
mac charset = MAC_ROMAN
invisible dots = yes
search db = yes
valid user = userA userB

/etc/auto.misc on /media/usb type autofs (rw,relatime,fd=6,pgrp=1658,timeout=300,minproto=5,maxproto=5,indirect)
/dev/sdb2 on /media/usb/TimeCapsuleBackup type hfsplus (ro,nosuid,nodev,noexec,relatime,sync,umask=22,uid=0,gid=0,nls=utf8)
/dev/sdc2 on /media/usb/PogoPlug1 type hfsplus (ro,nosuid,nodev,noexec,relatime,sync,umask=22,uid=0,gid=0,nls=utf8)
/dev/sdd2 on /media/usb/OSX-Exchange type hfsplus (ro,nosuid,nodev,noexec,relatime,sync,umask=22,uid=0,gid=0,nls=utf8)

drwxrwxrwx 1 evils evils   20 Feb 27 01:24 OSX-Exchange
drwxrwxr-x 1 evils evils   18 Feb 27 01:19 PogoPlug1
drwxrwxr-x 1 root  root    12 Feb 27 01:00 TimeCapsuleBackup

Feb 27 00:59:08.422374 cnid_dbd[3314] {netatalk_conf.c:196} (W:AFPDaemon): volume "TimeMachineFH" does not support Extended Attributes or read-only volume
Feb 27 00:59:08.423147 cnid_dbd[3314] {netatalk_conf.c:196} (W:AFPDaemon): volume "TimeMachineNS" does not support Extended Attributes or read-only volume
Feb 27 00:59:08.423549 cnid_dbd[3314] {netatalk_conf.c:196} (W:AFPDaemon): volume "PogoPlug1" does not support Extended Attributes or read-only volume
Feb 27 00:59:08.423828 cnid_dbd[3314] {netatalk_conf.c:196} (W:AFPDaemon): volume "OSX-Exchange" does not support Extended Attributes or read-only volume
Feb 27 01:04:34.658562 cnid_metad[3460] {netatalk_conf.c:196} (W:AFPDaemon): volume "TimeMachineFH" does not support Extended Attributes or read-only volume
Feb 27 01:04:34.659329 cnid_metad[3460] {netatalk_conf.c:196} (W:AFPDaemon): volume "TimeMachineNS" does not support Extended Attributes or read-only volume
Feb 27 01:04:34.659725 cnid_metad[3460] {netatalk_conf.c:196} (W:AFPDaemon): volume "PogoPlug1" does not support Extended Attributes or read-only volume
Feb 27 01:04:34.660002 cnid_metad[3460] {netatalk_conf.c:196} (W:AFPDaemon): volume "OSX-Exchange" does not support Extended Attributes or read-only volume
Feb 27 01:04:34.799875 afpd[3459] {netatalk_conf.c:196} (W:AFPDaemon): volume "TimeMachineFH" does not support Extended Attributes or read-only volume
Feb 27 01:04:34.800798 afpd[3459] {netatalk_conf.c:196} (W:AFPDaemon): volume "TimeMachineNS" does not support Extended Attributes or read-only volume
Feb 27 01:04:34.801209 afpd[3459] {netatalk_conf.c:196} (W:AFPDaemon): volume "PogoPlug1" does not support Extended Attributes or read-only volume
Feb 27 01:04:34.801534 afpd[3459] {netatalk_conf.c:196} (W:AFPDaemon): volume "OSX-Exchange" does not support Extended Attributes or read-only volume
Feb 27 01:04:53.508492 afpd[3464] {netatalk_conf.c:196} (W:AFPDaemon): volume "TimeMachineFH" does not support Extended Attributes or read-only volume
Feb 27 01:04:53.508942 afpd[3464] {netatalk_conf.c:196} (W:AFPDaemon): volume "TimeMachineNS" does not support Extended Attributes or read-only volume
Feb 27 01:04:53.509239 afpd[3464] {netatalk_conf.c:196} (W:AFPDaemon): volume "PogoPlug1" does not support Extended Attributes or read-only volume
Feb 27 01:04:53.509531 afpd[3464] {netatalk_conf.c:196} (W:AFPDaemon): volume "OSX-Exchange" does not support Extended Attributes or read-only volume

Feb 27 01:05:08.355873 afpd[3467] {ad_open.c:976} (E:Default): ad->ad_ops->ad_mkrf(ad_p) failed: Permission denied

/dev/sXXX /media/usb/volume_name type hfsplus rw,nosuid,nodev,noexec,relatime,sync,umask=22,uid=0,gid=0,nls=utf8

sudo mount /dev/XXX /media/usb/volume_name -t hfsplus -o rw,nosuid,nodev,noexec,relatime,sync,umask=22,uid=0,gid=0,nls=utf8

[MyVolume]
...
appledouble = v2
ea = none