Unknown PCM error returned

[lryindra]

I have bluez-alsa working on a ubuntu 16.04 LTS where Libasound2 and alsa-utils are version 1.1.0-0

I got the following error when I setup the same config on Raspbian updated to buster release where libasound2 and alsa-utils are version 1.1.7. (also there is no alsa application available for this release):
$ aplay -D bluealsa ~/Music/piano2.wav
ALSA lib pcm.c:2565:(snd_pcm_open_noupdate) Unknown PCM bluealsa
aplay: main:828: audio open error: No such file or directory

bluez-alsa on the buster release of Rasbian does work when I call
$ aplay -D btheadset ~/Music/piano2.wav

Here is where btheadset is defined in ~/.asoundrc:
pcm.btheadset {
type plug
slave {
pcm {
type bluealsa
device XX:XX:XX:XX:XX:XX <------replace with headphone's real MAC
profile "sco"
}
}
hint {
show on
description "BT Headset"
}
}
ctl.btheadset {
type bluealsa
}

[lryindra]

I don't know why bluealsa is not in the pcm list (aplay --list-pcm), but this updated .asoundrc is working enough:

defaults.bluealsa.interface "hci0"
defaults.bluealsa.device "XX:XX:XX:XX:XX:XX"
defaults.bluealsa.profile "sco"
defaults.bluealsa.delay 10000

pcm.bluealsa {
@Args [HCI DEV PROFILE] <------------------this should be a lower case 'a'
@args.HCI {
type string
default "hci0"
}
@args.DEV {
type string
default "XX:XX:XX:XX:XX:XX"
}
@args.PROFILE {
type string
default "sco"
}
type plug
slave {
pcm {
type bluealsa
device $DEV
profile "sco"
}
}
hint {
show on
description "bluealsa"
}
}
ctl.bluealsa {
type bluealsa
}
pcm.btheadset {
@Args [DEV]
@args.DEV {
type string
default "XX:XX:XX:XX:XX:XX"
}
type plug
slave {
pcm {
type bluealsa
device $DEV
profile "sco"
}
}
hint {
show on
description "BT Headset"
}
}
ctl.btheadset {
type bluealsa
}