TOPIC: registration mails sent via Community Builder ?

Hi,
I was quite excited to use CMandrill for the first time tonight
I installed CMandrill, configured API, activated CMmandrill plugin.
But when I created a new (test) account from the front-end, the email was obviously not sent via Mandrill !?
After many many tests, always negative.
Hum. Then I thought "let's try from something else" :
1. I tried the "mass mail" component. Great ! There it would go through Mandrill (I see at the email "sent by ... on behalf of ...")
2. then I created a user not from Community Builder front-end, but from COM_USER backend. Great ! There too the mail did go through Mandrill
But what am I doing wrong with Community Builder ?? Is there some extra plugin to download ? Or some configuration to make ?
NB : In community builder configuration, the only think noteworthy is that I have filled in Welcome Email Subject and Welcome Email Body

Txs in advance for your very much appreciated help !
Marc

Well, it seems I make the questions and give the answers myself
But I must say, the issue was a bit tricky.
Actually, the explanation is the following :
- CMandrill works oviously with Joomla's native components WHATEVER is configured in Joomla's GLOBAL CONFIGURATION (PHP Mail, own SMTP, Sendmail)
- but for CMandrill to work also with Community Builder (and probably other external components I guess), Joomla's GLOBAL CONFIGURATION has to be set exclusively with SMTP (with credentials given by Mandrill. Also, apparently SMTP security should be set to NONE for it to work).
So hopefully I have found the explanation/workaround.
But Daniel or whoever may read this, feel free to validate or to comment !